The interval definitions in this timescale are derived from the following source:

• W. B. Harland, R. L. Armstrong, A. V. Cox, L. E. Craig, A. G. Smith and D. G. Smith. 1990. A Geologic Time Scale 1989. view

There are 11 timescales which overlap this one. show

• Obsolete Names for ICS Units
• Ten Million Year Bins
• Permian of the Russian Platform
• Permian of the Pamirs
• Permo-Triassic Subages of Eastern Europe
• Permian of Western Europe
• Permian of the Salt Range
• Permian of China
• Permian of North America
• Carbo-Permian of the Russian Platform
• Permian-Jurassic of New Zealand

This timescale is used in the definition of 68 collections