APA (7th ed.) Citation

Ďuďa, R., & Rejl, L. (1998). World of gemstones. Geoscience Press.

Chicago Style (17th ed.) Citation

Ďuďa, Rudolf, and Luboš Rejl. World of Gemstones. Tucson: Geoscience Press, 1998.

MLA (9th ed.) Citation

Ďuďa, Rudolf, and Luboš Rejl. World of Gemstones. Geoscience Press, 1998.

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