p365-347. LEXICON PUBLICATIONS. Philippines, 1979
2. Lorimer, Lawrence; “Marijuana” Encyclopedia Year Book 1993.
p214-215.
GROLIER INCORPORATED. Canada, 1993
3. Snyder, Solomon. The Encyclopedia of Psychoactive Drugs. Series 2.
LEGALIZATION: A DEBATE. CHELSEA HOUSE PUBLISHERS. New York, 1988
341