Cita APA (7th ed.)

Boegel, H. (1971). A collector's guide to minerals and gemstones. Thames and Hudson.

Cita Chicago (17th ed.)

Boegel, Hellmuth. A Collector's Guide to Minerals and Gemstones. London, England, United Kingdom: Thames and Hudson, 1971.

Cita MLA (9th ed.)

Boegel, Hellmuth. A Collector's Guide to Minerals and Gemstones. Thames and Hudson, 1971.