1. Combes, A. Bull. Soc. Chim. Fr. 1888, 49, 89. Alphonse-Edmond Combes (1858–1896) was born in St. Hippolyte-du-Fort, France. He apprenticed with Wurtz at Paris. He also collaborated with Charles Friedel of the Friedel-Crafts reaction fame. He became the president of the French Chemical Society in 1893 at the age of 35. His sudden death shortly after his 38th birthday was a great loss to organic chemistry.
2. Roberts, E. and Turner, E. J. Chem Soc. 1927, 1832. (Review).
3. Elderfield, R. C. In Heterocyclic Compounds, Elderfield, R. C., ed., Wiley & Sons, New York, 1952, vol. 4, 36–38. (Review).
4. Popp, F. D. and McEwen, W. E. Chem. Rev. 1958, 58, 321–401. (Review).
5. Coscia, A. T.; Dickerman, S. C. J. Am. Chem. Soc. 1959, 81, 3098.