Mapa mundial de los suelos . - 1: 5 000 000 . - Paris : UNESCO < 6.550/001 v >
Geologic map of North America / compiled by John C. Reed, Jr., John O. Wheeler and Brian E. Tucholke . - 1: 5 000 000 . - Boulder : Geological Society of America, 2005 . - 103 x 180 cm < 6.550/022 v >