1. Lednicer, D.; Mitscher, L. A. In The Organic Chemistry of Drug Synthesis; John Wiley and Sons: New York, 1980; Vol. 2, p. 387–390.
2. (a) Zeneca, Drug Data Report, 1990, 12 (11), 856; US 4886800;
3. (b) Pharmacia & Upjohn, Drug Data Report, 1991, 13 (4), 332; US 48268837;
4. (c) Mitsubisi Chem., Drug Data Report, 1994, 16 (2), 129;
5. (d) Pierre Fabre, Drug Data Report, 1993, 15 (10), 910; WO 93/09098.