Robert-Piessard, Sylvie; Le Baut, Guillaume; Courant, Jacqueline; Brion, Jean-Daniel; Sparfel, Louis; et al.
European Journal of Medicinal Chemistry, 1990 , vol. 25, # 1 p. 9 - 19

Barluenga, Jose; Montserrat, Javier M.; Florez, Josefa
Tetrahedron Letters, 1992 , vol. 33, # 41 p. 6183 - 6186