Preparation of some 10,10-dimethyltricyclo[7.1.1.0 2,7]undecenones and 9,9-dimethyltricyclo[6.1.1.0 2,6]-decenones from 2-pinene and 2(10)-pinene - Kopsa-Moilanen, Vieno (Chemica : Series A, 1993)