1. Department of Molecular Evolution, Centro de Astrobiología (CAB), INTA-CSIC, Madrid, Spain.
2. Departament of Física y Matemáticas y de Automática, University of Alcalá de Henares (UAH), Madrid, Spain.
3. Department of Natural Resource Sciences, McGill University, Québec, Canada.
4. Space Science Division and Astrobiology Division, NASA Ames Research Center, Moffett Field, California, USA.
5. Carl Sagan Center, SETI Institute, Mountain View, California, USA.