PRECURSORS 806,094 Precursors and chemicals frequently used in the illicit manufacture of narcotic drugs and psychotropic substances : report of the International Narcotics Control Board for 1997 on the Implementation of Article 12 of the United Nations Convention against Illicit Traffic in Narcotic Drugs and Psychotropic Substances of 1988 / International Narcotics Control Board. - New York : United Nations, 1998. - VII, 89 s. s il. , 29 cm. - (United Nations Publication ; no. E.98.XI ) ISBN 92-1-148105-8