1. Aczel P (1988) Non-well-founded Sets. CSLI, Stanford
2. Alexander S (1920) Space, Time, and Deity, vol 1 & 2. MacMillan, London
3. Ali SM, Zimmer RM (1997) The question concerning emergence. In: CASYS’97, Abstract book. First international conference on computing anticipatory systems CHAOS asbl
4. Allen TF (2006) A summary of the principles of hierarchy theory http://www.isss.org/hierarchy.htm
5. Aristote (1991) Métaphysique tome 2 Livres H-N Vrin