1. Serp/Figueiredo Chapters 4 8;
2. Benaglia p. 15 f; Ding/Uozumi; Bartholomew/Farrauto‐2 p. 45 f; Stiles; Hartley; Yermakov/Zakharov/Kuznetsov; Ullmann Vol.A5 p.347;
3. McKetta‐1 Vol. 7 p.1;
4. Dörwald; Schüth/Sing/Weitkamp; Kirschning; Hagen p.166;