1. The Oxford English Dictionary,1989
2. Stevenson, T. (1885). Poisons. In Encyclopaedia Britannica, 9th ed. 19, 275–279.
3. The Meaning of Poison;Stevenson,1959
4. History and scope of toxicology;Gallo,1991
5. Poisons and poisoners through the ages;Smith;Medico-Legal J.,1952