^Darias, V.; Bravo, L.; Abdallah, S. S.; Sánchez Mateo, C. C.; Expósito-Orta, M. A.; Lissavetsky, J.; Manzanares, J. Synthesis and preliminary pharmacological study of thiophene analogues of the antipyretic and analgesic agent ethenzamide. Archiv der Pharmazie. 1992, 325 (2): 83–87. PMID 1605721. doi:10.1002/ardp.19923250206.
^Wang, P. J.; Guo, H. R. Frequent analgesics consumption in migraineurs: Comparison between chronic and episodic migraineurs. The Journal of Headache and Pain. 2004, 5: 30. doi:10.1007/s10194-004-0065-x.