OPEN University of Sri Lanka Abeysekera, A,M. Karunatilaka, S. Course of study leading to the degree of bachelor of science level 4, PSU 2114-o /by A.M.Abeysekera, S.Karunatilaka - Nugegoda The Open Univeristy of Sri Lanka 1986 - 161 p. Includes glossary. ISBN: 141617 Dewey Class. No.: 547 / OPE