1. Interlevel relations in ecological research and management: some working principles from hierarchy theory;Allen,1984
2. Hierarchy: Perspectives for Ecological Complexity;Allen,1982
3. Extraterrestrial cause for the Cretaceous-Tertiary extinction;Alvarez;Science,1980
4. The Physical Basis of Life;Bernal,1951
5. Problems of Life: An Evaluation of Modern Biological Thought;Bertalanffy,1952