1. Colorimetric Determinations of Chlorpheniramine Maleate, Ephedrine Hydrochloride, and Guaiacolsulfonate Potassium in a Cough Syrup
2. “The Merck Index”, 9th ed., Merck & Co., Rahway, N.J., no. 7415.
3. “The National Formulary”, 13th ed., Mack Publishing Co., Easton, Pa., p. 574.