Ramanathan, V. S.; Chandra, P. (1980). "Recovery of thebaine and cryptopine from Indian opium". Bulletin on Narcotics. 32 (2): 49–63. ISSN0007-523X. PMID6907026.
Ramanathan, V. S.; Chandra, P. (1980). "Recovery of thebaine and cryptopine from Indian opium". Bulletin on Narcotics. 32 (2): 49–63. ISSN0007-523X. PMID6907026.