1. Schon, D. Beyond the stable state, Temple Smith, 1971:51.
2. Wilber, K. Sex, ecology, spirituality: the spirit of evolution. Boston, Shambhala, 1995:410.
3. Wilber, op cit, reference 2, p. 418.
4. Wilber, op cit, reference 2, p. 121.
5. Wilber, op cit, reference 2, p. 121.