Armer, Richard E.; Barlow, Jacqueline S.; Dutton, Christopher J.; Greenway, David H.J.; Greenwood, Sean D.W.; Lad, Nita; Tommasini, Ivan
Bioorganic and Medicinal Chemistry Letters, 1997 , vol. 7, # 20 p. 2585 - 2588

Drake et al.
Journal of the American Chemical Society, 1946 , vol. 68, p. 1529