TY  - BOOK
AU  - Vidya Ratan
TI  - Viva in Preventive and Social Medicine(Hygiene and Public Health)
SN  - 81-7179-785-7
U1  - 614.44 
PB  - Newdelhi: Jaypee Brothers Medical Publishing Ltd
N1  - the Eastern University of Srilanka
ER  -