APA (7th ed.) Citation

Ridgway, R. H. (1930). Sulphur: General information. [publisher not identified].

Chicago Style (17th ed.) Citation

Ridgway, Robert H. Sulphur: General Information. Washington, D.C.: [publisher not identified], 1930.

MLA (9th ed.) Citation

Ridgway, Robert H. Sulphur: General Information. [publisher not identified], 1930.

Warning: These citations may not always be 100% accurate.