This page lists the sources behind the globe. Each site, animal, comparison and rock layer in the tool ends with a line of numbers, and each number links to its entry here.
Peer-reviewed papers and monographs come first. Geological surveys, museums, park services and universities come second. Science press appears only for framing and never as the sole source for a number. Encyclopaedias, blogs and dealers are not cited. A claim that could not be traced to a source of the first two kinds was removed from the tool.