Further reading
- 1999, World Futures: Operators, the Lego-bricks of Nature: Evolutionary transitions from fermions to neural networks
- 2001, Acta Biotheoretica: Extrapolating a hierarchy of building block systems towards future neural network organisms
- 2001, Essaybundel Kennisdisseminatie: Technische intelligentie is volgend stadium in de evolutie (Dutch)
- 2008, Biological Reviews: Analysing hierarchy in the organization of biological and physical systems
- 2010, PhD thesis: The operator hierarchy, a chain of closures linking matter, life and artificial intelligence
- 2010, Foundations of Science: Hierarchical definition of life
- 2010 Nijmegen (powerpoint) : PhD presentation
- 2010 (powerpoint) Biennale Arnhem: Toeval en evolutie
- 2010 (powerpoint) ECCO, Brussels: Evolution Ladder step by step
- 2011 (powerpoint) INBIOSA, Stirling: The elephant lecture