El-Abadla, Naser; Lampilas, Maxime; Hennig, Lothar; Findeisen, Matthias; Welzel, Peter; Mueller, Dietrich; Markus, Astrid; Van Heijenoort, Jean Tetrahedron, 1999, vol. 55, # 3 p. 699 - 722 doi: 10.1016/S0040-4020(98)01063-1