@ARTICLE { AUTHOR = "Mar{\'{\i}}a Luisa C{\'a}rdenas and Juan Carlos Letelier and Athel Cornish-Bowden and Jorge Soto-Andrade and Claudio Gutierrez", TITLE ="Closure to Efficient Causation, Computability and Artificial Life", JOURNAL = "Journal of Theoretical Biology (JTB)", VOLUME = "263", NUMBER = "1", PAGES = "79-92", MONTH = "Mar", YEAR = "2010", PUBLISHER = "Elsevier Science", ADDRESS = "Amsterdam, The Netherlands", ISSN = "0022-5193" }