Citation analysis of doctoral dissertations in Chemistry

CITATION ANALYSIS OF DOCTORAL DISSERTATIONS IN CHEMISTRY

Citations of22doctoral dissertations in chemistry submitted to Mangalore University since its incep- tion were analysed to study the information use pattern of researchers. The study has identified 60 core journals, out of total 418journals, referred to by the researchers. The application of Bradford's Law of Scattering to the literature of chemistry reveals an exponential trend when plotted onthe graph. The Bradford's multiplier is seen to observe

a

INTRODUCTION

The term Bibliometrics was first introduced by Pritchard [15] in preference to the term Statistical Bibliography coined by Hulme in 1923. Pritchard was of opinion that the term statistical bibliogra- phy has some ambiguity in it and the likelihood of it being misinterpreted as bibliography of statistics.

Roy [16] has defined bibliometrics as a study of the process of information use by analysing the characteristics of documents and their distribution by statistical methods. Garfield [7] in his studies pointed-out that sources of most frequent citations on a journal provide an indication of the intra-jour- nal communication network associated with a par- ticular journal and they could give valuable clues to the transfer and sharing of information within and between disciplines.

In a recent study of dissertations in the German Democratic Republic (GDR). Mertens [13] has clearly pointed out the rigid policy of GDR in treat- ing the doctoral dissertations as a state secret and confidential matter putting hindrence to the dissemi- nation of research in various diciplines of science.

More than 6800 titles were not listed in national bibliographies in GDR out of the total 41000 dis- sertations.

Bibliometric studies have been going on in India for the last three decades [4, 14, 18, 19, 20].

(Mrs.) M. A. MUBEEN Mangalore University Library Mangalagangotri - 574199

Hiremath and Sangam [8] carried out a citation analysis of doctoral dissertations in Chemistry.

Sangam [17] did a study on the information use pattern of researchers in the field of psychology.

Subramanyan [21] studied the information seek- ing behaviour of doctoral candidates in social sci- ences. Lal [9] studied the trend of citation pattern in agricultural research in Bihar and identified 59 most cited journals in the field of agriculture.

Maheswarappa and Prakash [11] carried out a study of the literature use pattern by the research- ers in the field of Botany. Recently, Madkey and Rajyalakshmi [10] carried out a citation analysis of Ph.D. theses submitted by NEERI scientists in the field of environmental sciences and engineering during 1977-91. In this study, a list of 67 core jour- nals have been identified in the field and a total of 31 theses yielded 5466 citations.

The objectives of the present study are to identify:

i) the use of different sources of information and their dispersion on the basis of SUbject,COW1-

try and language;

ii) the use of important journals and their avail- ability at Mangalore University library; and iii) to find out the authorship pattern and to check

whether Bradford's Law of Scattering applies to the journal use pattern of researchers in chemistry.

METHODOLOGY AND SAMPLE

Twenty two doctoral theses accepted by Mangalore University during the period 1980-93 in chemistry have been considered for the present study. Of these theses, nine are on inorganic chemistry, four on organic chemistry and nine on physical chem- istry.

All the citations belonging to journal and non-jour- nal publications were noted on a plain paper under

CITATION ANALYSIS OF DOCTORAL DISSERTATIONS IN CHEMISTRY

different heads with the year of publication, whereas each citation of journal was recorded on a sepa- rate 5" x 3" slip with the indication of the journal, year of publication, volume, issue, page number and title of the journal. These citations were clas- sified and analysed according to bibliographic form, subject, country of origin, authorship pattern for fur- ther study. Twenty two Ph.D. theses accepted by the Mangalore University, included 5012 citations,

i.e., about 228 citations per thesis on an average.

DISTRIBUTION OF CITATIONS ACCORDING TO BIBLIOGRAPHIC FORM

Of the 5012 citations, as many as 3659 (73%) per- tained to journals, 575 (11.48%) to books, 463 (9.24%) to patents, and the rest 315 (6.28%) to technical bulletins, conference proceedings, the- ses and technical reports and so on (Table 1).

Table 1

Distribution of citations according to bibliographic forms

Sl.no. Bibliographic form Citation Percentage

1. Journals 3659 73.00

2. Books 575 11.48

3. Patents 463 9.24

4. Technical Bulletins 118 2.36

5. Conference Proceedings 88 1.76

6. Theses 43 0.86

7. Others 66 1.30

Total 5012 100.00

COUNTRYWISE CITATIONS

It is noticed from the cited documents that the re- search scholars in chemistry have referred to the literature from 27 countries (Table 2). Of all the countries, USA dominates accounting for 1514 (30.2%) citations, India follows next with a list of

1003 (20%) citations. UK occupies the third place with a total of 968 (19.31%) citations followed by Germany, USSR and Japan occupy fourth, fifth and sixth places with 360 (7.18%),303 (6%), 251 (5%) citations respectively. The researchers have re- ferred to only 12.2% of the citations from the re- maining 21 countries.

Table 2

Country VS. Bibliographic form wise distribution of cited documents

Citations

Sl.no. Country Journals Books Patents Theses Others Total Percentage

1. U.S.A. 1075 286 79 0 74 1514 30.20

2. India 910 16 0 41 36 1003 20.01

3. UK 668 202 34 2 62 968 19.31

4. Germany 220 6 108 0 26 360 7.18

5. U.S.S.R. 229 8 20 0 ⁴⁶ 303 6.05

6. Japan 118 7 108 0 18 251 5.01

7. Holland 25 50 17 0 2 94 1.75

8. Italy 72 0 0 0 6 78 1.56

9. Australia 50 0 0 0 0 50 1.00

10. Bulgaria 29 0 19 0 0 48 0.96

11. France 22 0 25 0 0 47 0.94

12. Czechkoslokia 38 0 9 0 0 47 0.94

13. Switzerland 37 0 8 0 0 45 0.90

14. Hungary 30 0 0 0 0 30 0.60

15. China 25 0 0 0 0 25 0.50

16. Canada 10 0 13 0 0 23 0.46

17. South Africa 7 0 16 0 0 23 0.46

18. Poland 22 0 0 0 0 22 0.44

19. Denmark 18 0 0 0 0 18 0.36

20. Austria 16 0 0 0 0 16 0.32

21. Spain 16 0 0 0 0 16 0.32

22. Israel 4 0 7 0 0 11 0.22

23. Rumania 11 0 0 0 0 11 0.22

24. Yugoslavia 4 0 0 0 0 6 0.12

25. Cuba 1 0 0 0 0 1 0.02

26. Egypt 1 0 0 0 0 1 0.02

27. Greece 1 0 0 0 0 1 0.02

Total 3659 575 463 43 272 5012 100.00

LANGUAGE WISE DISTRIBUTION tions were in English and all other languages put together accounted for 1034 (20.6%) citations.

These languages are German, Russian, Japanese, French, Italian, Czeek and Hungarian.

The English as a language of communication oc- cupies the prime place among the researchers of chemistry (Table 3). A total of 3978 (79.4%) cita-

CITA TlON ANAL YSIS OF DOCTORAL DISSERTATIONS IN CHEMISTRY

Table 3

Language wise distribution of cited documents

SI. no. Language Citations Percentage

1. English 3978 79.4

2. German 279 5.6

3. Russian 214 4.3

4. Japanese 200 4.0

5. French 89 1.8

6. Italian 69 1.3

7. Czech 36 0.7

8. Hungarian 33 0.6

9. Others 114 2.3

Total 5012 100.00

AUTHORSHIP PATTERN authored contributions with a total of 829 (22.66%) and three authored contributions of 562 (15.36%).

The remaining articles are contributed by four or more authors.

Table 4 shows the authorship pattern as reflected in journal articles. Single author contributions ag- gregate to 1006 (27.49%) citations; followed by two

Table 4

Authorship pattern of journal citations

No. of authors No. of citations Percentage

Single author 1006 27.49

Two authors 829 22.66

Three authors 562 15.36

Four authors 545 14.89

Five authors 379 10.36

Six authors 204 5.58

Seven or more authors 134 3.66

Total 3659 100.00

CORE LIST OF JOURNALS

Table 5 gives the list of journals cited by research- ers. Of the 418 journals, 58 journals have been cited at least 10 times or more. These 58 journals account for 2722 (74.45%), out of 3659 citations.

The first 30 journals accounted for nearly 63% and the remaining 28 journals have slightly more than 11% citations. The remaining 360 journals with 937 citations (25.61%) have less than 10 citations each.

Among the journals, Indian Journal of Chemistry

occupies the top slot accounting for 14% citations and is followed by Journal of the Indian Chemical Society with a share of slightly more than 7% of the citations. Talanta occupies the third place. Out of 58 journals, five journals are from India, account- ing for slightly less than a quarter of the total cita- tions. Mangalore University library possesses 19 journals out of these 58 ranked journals. 7 out of the first 10 ranked journals are available in Mangalore University library.

TableS

Rank list of journals in chemistry

SI. Rank Joumal title No. of Cumulative Percentage Cumulative Country

no. no. citations citations %

01 01 Indian Joumal of Chemistry 512 512 14.00 14.00 India

02 02 Joumal of Indian Chemical Society 288 800 7.87 21.87 India

03 03 Talanta 132 932 3.61 25.48 U.K.

04 04 Journal of American Chemical Society 128 1060 3.49 28.97 U.S.A.

05 O!? Joumal of Medicinal Chemistry 99 1159 2.71 31.68 U.S.A.

06 06 Journal of Inorganic & Nuclear Chemistry 86 1245 2.35 34.03 U.K.

07 07 Current Science 82 1327 2.24 36.27 India

08 08 Journal of Heterocyclic Chemistry 80 1407 2.19 38.46 U.S.A.

09 09 Journal of Chemical Society Perkin 74 1481 2.02 40.48 U.K.

Transactions I

10 10 Inorganic Chemistry 69 1550 1.89 42.37 U.S.A.

11 11 Joumal of Organic Chemistry 66 1616 1.80 44.17 U.S.A.

12 12 Journal of Chemical Society 58 1654 1.58 45.75 Japan

13 13 Tetrahedron 58 1732 1.58 47.33 U.S.A.

14 14 Zeitschrift Analyt. Chemie 49 1781 1.34 48.67 Germany

15 14 Zeitschrift fur Physikalische Chemie 41 1822 1.12 49.79 Germany

16 14 Australian Joumal of Chemistry 41 1863 1.12 51.91 Australia

17 14 Analytical Chemistry 41 1904 1.12 52.03 ^U.S.A.

18 15 Journal of Chemical Physics 39 1943 1.06 53.09 U.S.A.

19 15 International Journal of Chemical Kinetics 39 1982 1.06 54.15 ^U.S.A.

20 16 Chemical Reviews 33 2115 0.90 55.05 U.S.A.

21 16 Chemical Analysis 33 2048 0.90 55.95 U.S.A.

22 16 Joumal of Chemical Society Faraday 33 2081 0.90 56.85 U.K.

Transactions-II

23 16 Zhurnal Analiticheskoi Khimii 33 2114 0.90 57.75 U.S.S.R

24 17 Journal of Chemical Society Dalton 30 2144 0.81 58.56 U.K.

Transactions

25 17 Microchemical Joumal 30 2174 0.81 59.37 ^U.S.A.

26 18 Inorganic Chemica Acta 26 2200 0.71 60.08 Italy

27 19 Canadian Joumal of Chemistry 23 2223 0.63 60.71 Canada

28 19 Joumal of Physical Chemistry 23 2246 0.63 61.34 U.S.A.

29 19 Yakagaku Zasshi 23 2269 0.63 62.97 Japan

30 19 Analysts 23 2292 0.63 62.60 U.K.

31 20 Nature 20 2312 0.54 63.14 U.K.

contd.

CITATION ANALYSIS OF DOCTORAL DISSERTATIONS IN CHEMISTRY

Table 5 (contn.)

SI. Rank Journal title No. of Cumulative Percentage Cumulative Country

no. no. citations citations ^0/0

32 20 Oxidation Communication 20 2332 0.54 63.58 Bulgaria

33 20 Zeitschrift Fuer Natorforchung 20 2352 0.54 64.12 Germany

34 20 Journal of Chemical Education 20 2372 0.54 64.66 U.S.A.

35 21 Journal of Biochemistry 17 2389 0.46 65.12 U.S.A.

36 21 Journal of Chemical Research 17 2406 0.46 65.58 U.K.

37 21 Synthesis and Reactivity in Inorganic & 17 2423 0.46 66.04 U.S.A.

Metalorganic Chemistry

38 21 Zavodskya Laboratoria 17 2440 0.46 66.50 U.S.S.R

39 21 Macrochemica Acta 17 2457 0.46 67.96 Australia

40 21 British Corrosion Journal 17 2474 0.46 67.42 U.K.

41 21 Journal of Pharmaceutical Science 17 2491 0.46 68.88 U.S.A.

42 22 Spectrochemica Acta 15 2506 0.41 68.29 U.S.A.

43 22 Journal of American Pharmaceutical 15 2521 0.41 68.70 U.S.A.

Association

44 22 Journal Electro-Chemical Society 15 2536 0.41 69.11 U.S.A.

45 22 Zhurnal Obshchei Khimii 15 2551 0.41 69.52 U.S.S.R

46 22 Indian Journal of Technology 15 2566 0.41 70.93 India

47 23 Indian Journal of Applied Chemistry 13 2579 0.36 70.29 India

48 23 Electrochemica Acta 13 2592 0.36 70.65 U.K.

49 23 Acta Chemica Scandinavica 13 2605 0.36 71.01 Denmark

50 23 Fenxi Hauzere 13 2618 0.36 71.37 China

51 23 Zeitschrift Fuer Analytische Chemie 13 2631 0.36 71.73 U.S.S.R

52 23 Kimiko Farmatsevticheskii Zhurnal 13 2644 0.36 72.09 U.S.S.R

53 23 Khim Geterotsikl Soedin 13 2657 0.36 72.45 U.S.S.R.

54 ~3 Kinetics and Catalysis 13 2670 0.36 73.81 U.S.A.

55 23 Kinetica Kataliz 13 2683 0.36 73.17 U.S.A.

56 23 Kogyo Kagaku Zasshil 13 2696 0.36 73.53 Japan

57 23 Pharmazie 13 2709 0.36 73.89 Germany

58 23 Zeitschrift Fuer Anorganische und 13 2722 0.36 74.39 Germany

Allegemeine Chemie Remaining 360 titles cited

less tan 10 citations 937 3659 25.61 100.00

-

BRADFORD'S LAW OF SCATTERING

Bradford [2] formulated a simple mathematical model to describe reference scattering. Cole [5]

statistically explained that "by plotting the cumula- tive fraction of total reference against the logarithm of the cumulative fraction total of titles, an approxi- mately linear curve is obtained and the slope of this curve gives a reference scattering which may be characteristics of this study". Zipf [22] proposed his Principle of Least Effort whose graphical ex- pression is a straight line. Brookes [3] later ex- pressed Bradford's Law in mathematical terms that has practical significance to librarianship and docu- mentation.

The graphical and verbal interpretation of the Bradford's Law of Scattering has been applied to the literature of chemistry. Table 6 represents jour- nals arranged in decreasing frequency of citations.

To testify the applicability of Bradford's Law of Scat- tering, a graph is plotted by taking the cumulative number of citations on "y" axis and log of cumula- tive number of journals on "x" axis. It is observed that the resulting bibliograph, starts raising in an exponential nature and then follows the linear curve indicating the observance of Bradford's Law of Scattering.

Table 6

Distribution of cited journals by decreasing frequencies of citations

No. of Cumulative Log of No. of Total Cumulative %of %of

journals no. of cumulative citations citations citations Cumulative Cumulative

journals journals citations journals

1 1 0.00 512 512 512 14.00 0.24

1 2 0.30 288 288 800 21.87 0.48

1 3 0.48 132 132 932 25.47 0.71

1 4 0.60 128 128 1060 28.97 0.95

1 5 0.70 99 99 1159 31.67 1.19

1 6 0.78 86 86 1245 34.02 1.43

1 7 0.84 82 82 1327 36.26 1.67

1 8 0.90 80 80 1407 38.45 1.91

1 9 0.95 74 74 1481 40.47 2.11

1 10 1.00 69 69 1550 42.36 2.39

1 11 1.04 66 66 1616 44.16 2.63

2 13 1.11 58 116 1732 47.33 3.11

1 14 1.14 49 49 1781 48.67 3.34

3 17 1.23 41 123 1904 52.03 4.06

2 19 1.27 39 78 1982 54.16 4.54

4 23 1.36 33 132 2114 57.77 5.50

2 25 1.39 30 60 2174 59.41 5.98

1 26 1.41 26 26 2200 60.12 6.22

4 30 1.48 23 92 2292 62.64 7.17

4 34 1.53 20 80 2372 6 \.82 8.13

7 41 1.61 17 119 2491 68.07 9.80

5 46 1.66 15 75 2566 70.12 11.00

12 58 1.76 13 156 2722 74.39 13.87

14 72 1.85 9 126 2848 77.83 17.22

12 84 1.92 8 96 2944 80.45 20.09

8 92 1.96 7 56 3000 81.98 22.00

9 101 2.00 6 54 3054 83.46 24.16

15 116 2.06 5 75 3129 85.51 27.75

30 146 2.16 4 120 3249 88.79 34.92

30 176 2.24 3 90 3339 91.25 42.10

78 254 2.40 2 156 3495 95.51 60.76

164 418 2.62 1 164 3659 100.00 100.00

Here, it is observed that an experimental curve (continuous line) is closely in association with the theoretical line (dotted line) up to about 3500 cita- tions and then starts dropping as shown in Fig 1.

If Bradford's law is applicable to the data, it would also follow the algebric interpretation of the law.

For the algebric interpretation of the law, the col- lection of journals containing citations may be clas- sified into 'N' zones or classes" of decreasing pro-

*In fact, Maia and Maia (12) make no distinction between zone and class; for detailed version of the derivations ofthe Bradford's zones and multiplier factor please refer to their work.

ductivity, defined by an integer K,= 1,2,3, ....N. The smaller values of 'K' correspond to the most pro- ductive class. Let Pkbe the number of periodicals and mkbe the number of articles in the class 'k'.

Then, the mean number of articles per periodical in the class 'k' is

m

r_k =

CITATION ANALYSIS

OF

i

y

4000

SCALE

Xl: 1cm

=

=

3200

2800 2400 Y.

2000

1600

1200~ ~rv

Y. /

/ / / /

/ / / / / /

O~/~__-i~X~'~L-

~~X~a~~~~~--~~--~~----~--

'4 -8 1-2 1-6 2·0 2-4 2·8 3-2 X

LOG OF CUMULATIVE NUMBER OF JOURNALS

log (X )--+") 400

Fig. 1 Bradford's bibliograph

The entire Bradford's law can be divided into two hypotheses; the first hypothesis defines the size of the class and it states that the number of articles is the same for any class and it is equal to a con- stant 'm' .

m,

m

m3

m

Then (1) becomes m

(3)

Therefore, the classes are classified in order of de- creasing productivity and it folows that

then, automatically using (3) we get

or

But from (3) it follows that

and dividing this by Pk-1rk

rk_1 P^k m

-, -- =

Denoting m

a

= ---

^z

then, from (5)

(7) kz 2

At this juncture, we bring in the second hypothesis assumed by Bradford that "there is no reason to suppose that the values a1, a2, a3 •••••• anare dif- ferent. Therefore, we can assume that they are

equal to a common constant 'a':

Though the hypothesis is too restrictive, its valid- ity depends on the way in which the division of collections in classes has been made so that the ratio rk.,lrk remains constant for any k, so that the value can be determined from the equations (5) and (6) :

rk_1 Pk

a = = k~ 2 (8)

rk P^k-1

Infact, even in the original work of Bradford, the multiplier factor for both Applied Geophysics and Lubrication is not constant. Here, Maia and Maia [12] suggest that the mean of the multiplier factors more or less gives a constant 'a' value; and the factor so obtained fits prefectly with the Bradford's Law. For the algebric interpretation of the Law, the citations have been arranged into three zones of 1159, 1407 and 1093 respectively.

The scatter of chemistry literature over Bradford's zone, following the works of De Queriroz and Lancaster [6] and Maia and Maia [12], is given in Table 7. The Bradford's multiplier factor is calcu- lated by using formula (8). The multiplier factors for two zones are 8.2 and 9.07 respectively, the mean of which works out to 8.6. From Table 7, the findings can be shown that the data follows Bradford's Law [2] viz.

5x 1 = 5

5x8.6

=

5x 8.6 x 8.6 = 370

In other words, it is 1 : a : a2 which is a proof of Bradford's Law.

CITATION ANALYSIS OF ^DOCTORAL DISSERTATIONS IN CHEMISTRY

Table 7

Scattering of citations in the Bradford's zones

Zone Journals Cumulative Cumulative Citations Multiplier

journals citations of zone factor

K

P

1 5 5 1159 1159

2 41 43 2566 1407 8.2

3 372 418 3659 1093 9.07

CONCLUSION

The analysis of the doctoral dissertations in chem- istry shows that researchers mainly depend on jour- nal sources for their information use. It is evident from the study that an overwhelming majority use 5.

English as their primary medium for their research.

This study confirms that the journal use patern of chemistry researchers fits well with the Bradford's 6.

Law of Scattering. Moreover, this study reveals that there are only a few countries which can be de- pended on for original research information. It is hoped that this study may enlighten the research- ers in identifying the primary sources of informa- tion. Studies of this nature will be helpful for the 7.

documentalists in circulating the contents for the use of potential readers and researchers; it can also serve as feedback to the librarians in the se- lection and acquisition of most useful journals within 8.

the budget constraints.

REFERENCES

1. ARORA (J) and KAUR (S P): Bibliometric analysis of core journals in Immunology: a study on the Annual Review of Immunology.

Ann. Lib. Sci. Doc. 41; 3; 1994; 81-94.

2. ^BRADFORD (S C): Documentation. 1948.

Crossby Lockwood; London.

3. ^BROOKES (B C): The derivation and appli- cation of the Bradford-zipf distribution. Jour.

Doc. 24, 4; 1968; 247-265.

4. CHAKRAVARTHY ((A R): Citation studies.

Workshop on Scientific Communication and Bibliometrics. 1988, Feb; Calcutta.

COLE (P F): A new look at reference scat- tering. Jour. Doc. 18,2; 1962; 58-64.

DE QUERIROZ (G S) and LANCASTER (F W): Growth, dispersion and obsolescence of the literature: a case study in thermolumi- nescent dosimetry. Jour. Res. Comm. Stud- ies. 82, 2; 1979; 203-217.

GARFIELD (E): Citation analysis as a tool in journal evaluation. Science. 178; 1972;

471-479.

HIREMATH (V R) and SANGAM (S L): A ci- tation analysis of doctoral dissertations in chemistry. SIS Convention on Scientific Communication: Bibliometrics/lnformetrics.

1988, Jan; Calcutta.

9. LAL (A): A trend in citation pattern in agri- culture research in Bihar. IASLIC Bull.34, 2;

1989; 65-72.

10. MADKEY (V D) and RAJYALAKSHMI (D):

Citation analysis of Ph.D. theses in environ- mental science and engineering used by NEERI scientists during 1977-1991. Ann.

Lib. Sci. Doc.41, 2; 1994; 63-78.

11. MAHESWARAPPA (B S) and PRAKASH (B P): Literature use pattern by the research- ers in the field of botany. Jour. Lib. Inf. Sci.

7, 1; 1982; 5-32.

12. MAlA (M J F) and MAlA (M D): On the unity of Bradford's Law. Jour. Doc. 40, 3; 1984;

206-216.

13. MERTENS (L): A state secret dissertations in the German Democratic Republic. Jour.

Doc. 50, 1; 1994; 1-9.

14. PAN WAR (S D) and JAIN (H C): Bibliometric study of the literature on medicinal and aro- matic plants. SIS Convention on Scientific Communication: Bibliometrics/lnformetrics.

1988, Jan; Calcutta.

15. PRITCHARD (A): Statistical bibliography of bibliometrics. Jour. Doc. 25, 4; 1969; 348- 349.

16. ROY (P M): Towards a theory of citing in a citation analysis studies. In: Developing ho- rizons in library and information science. Ed.

by Sharma C D and Kailas Vyas. 1983. vol.

1. Print Printwell; Jaipur. pp. 223-235.

17. SANGAM (S L): Information use pattern of researchers in the field of psychology: a ci- tation study. IASLIC Bull. 34, 2; 1989; 55- 63.

18. SATISH (N G) and INAMDAR (N B): Infor- mation use pattern of rural development sci- entists: a case study. ILA Bull.22,3-6; 1986- 87; 156-164.

19. SEN (B K): Bibliometrics - review of published literature. Workshop of Scientific Communi- cation and bibliometrics. 1988, Feb; Calcutta.

20. SINGH (G) and MUKHERJEE (T):

Bibliometric study of literature published in Indian Journal of Nematology 1981-86. SIS Convention on Scientific Communication:

Bibliometrics/lnformetrics. 1988, Jan;

Calcutta.

21. SUBRAMANYAN (T): Study of information seeking behaviour of doctoral candidates in social sciences. Her. Lib. Sci.22, 3-4; 1983;

200-204.

22. ZIPF (G K): Human behaviour and the prin- ciple of leaset effort. 1949. Addison - Wesley; Cambridge, Mass.