M. Li and P. Vitányi, An introduction to Kolmogorov complexity and its applications, 2008.

M. Vyugin, Information distance and conditional complexities, Theoretical Computer Science, vol.271, issue.1-2, pp.145-150, 2002.
DOI : 10.1016/S0304-3975(01)00037-8
URL : http://doi.org/10.1016/s0304-3975(01)00037-8

. An and . Muchnik, Conditional complexity and codes, Theoretical Computer Science, vol.271, issue.12, pp.97-109, 2002.