Navaratnam, V. (1990). A ten year retrospective follow-up of drug dependence career. Pusat Penyelidikan Dadah dan Ubat-Ubatan (Centre for Drug Research), Universiti Sains Malaysia.

Navaratnam, V. A Ten Year Retrospective Follow-up of Drug Dependence Career. Minden, Pulau Pinang: Pusat Penyelidikan Dadah dan Ubat-Ubatan (Centre for Drug Research), Universiti Sains Malaysia, 1990.

Navaratnam, V. A Ten Year Retrospective Follow-up of Drug Dependence Career. Pusat Penyelidikan Dadah dan Ubat-Ubatan (Centre for Drug Research), Universiti Sains Malaysia, 1990.