A Comparative Analysis of Obsolescence of Periodical Literature of Petroleum Geology

Age distributions of citations received by the American Association, of Petroleum Geologist Bulletin for the years 1960, 1970 and 1979 were analysed. Citation distributions were statistically tested by applying K-S Test, found to be negative exponential. Obsolescence factors were determined. The average halflife for 1960 data was found to be 7.6 years while 6.2 and 6.1 years for 1970 and 1979 respectively. The year 1970 received comparatively more citations than the others which shows increased research activity in seventies and more visibility and use of literature in these years. Percentage of citations for the first decades have increased from 60% to 70% from 1960 to 1970 and 1979 which indicates greater use of recent literature.