Hilbert, Martin; López, Priscila (2011). “The World's Technological Capacity to Store, Communicate, and Compute Information”. Science. 332 (6025): 60–65. Bibcode:2011Sci...332...60H. doi:10.1126/science.1200970. PMID21310967. Free access to the article at martinhilbert.net/WorldInfoCapacity.html
Hilbert, Martin; López, Priscila (2011). “The World's Technological Capacity to Store, Communicate, and Compute Information”. Science. 332 (6025): 60–65. Bibcode:2011Sci...332...60H. doi:10.1126/science.1200970. PMID21310967. Free access to the article at martinhilbert.net/WorldInfoCapacity.html
Hilbert, Martin; López, Priscila (2011). “The World's Technological Capacity to Store, Communicate, and Compute Information”. Science. 332 (6025): 60–65. Bibcode:2011Sci...332...60H. doi:10.1126/science.1200970. PMID21310967. Free access to the article at martinhilbert.net/WorldInfoCapacity.html