1. A. Kleemann, J. Engel, B. Kutscher, D. Reichert, Pharmaceutical Substances-Synthesis, Patents, Applications, fourth ed., Thieme, 2001.
2. European Pharmacopoeia, fourth ed., Council of Europe, Strasburg, 2002.
3. The United States Pharmacopoeia (USP26), 2003.
4. Stability studies of tetracycline in methanol solution
5. Chromatographic analysis of tetracycline antibiotics in foods