1. Arrabales, R., Ledezma, A., & Sanchis, A. (2010). ConsScale: A pragmatic scale for measuring the level of consciousness in artificial agents. Journal of Consciousness Studies, 17(3–4), 131–164.
2. Barbieri, M. (2001). The organic codes: The birth of semantic biology. Ancona: PeQuod. (Republished in 2003 as The organic codes. An introduction to semantic biology. Cambridge: Cambridge University Press).
3. Barbieri, M. (2011). Origin and evolution of the brain. Biosemiotics, 4, 369.
4. Barrow, J. D. (2007). New theories of everything. Oxford: Oxford University Press.
5. Barrow, J. D., Davies, P. C. W., & Harper, C., Jr. (Eds.). (2004). Science and ultimate reality. Quantum theory, cosmology, and complexity. Cambridge: Cambridge University Press.