↑(en) Jason W. Sahl, Raleigh Schmidt, Elizabeth D. Swanner, Kevin W. Mandernack, Alexis S. Templeton, Thomas L. Kieft, Richard L. Smith, William E. Sanford, Robert L. Callaghan, Jeffry B. Mitton et John R. Spear, « Subsurface Microbial Diversity in Deep-Granitic-Fracture Water in Colorado », Applied and Environmental Microbiology, vol. 74, no 1, , p. 143–152 (PMID17981950, PMCID2223202, DOI10.1128/AEM.01133-07, lire en ligne)