Jayawardhana, M.F.S.G පදාර්ථ සහ විකිරණ - Department of Education Publisher Battaramulla 1997 - 96p 1 - 2023-11-20 ISBN: 955-597-407-1 Nat. Bib. No.: 0007324 Nat. Bib. Agency Control No.: JAY Universal Decimal Class. No.: 530