Polk, P. (2016). Collecting rocks, gems and minerals: Identification, values, lapidary uses (3rd edition.). Krause Publications, a division of F+W Media, Inc..
Cita Chicago Style (17a ed.)Polk, Patti. Collecting Rocks, Gems and Minerals: Identification, Values, Lapidary Uses. 3rd edition. Iola, WI: Krause Publications, a division of F+W Media, Inc., 2016.
Cita MLA (8a ed.)Polk, Patti. Collecting Rocks, Gems and Minerals: Identification, Values, Lapidary Uses. 3rd edition. Krause Publications, a division of F+W Media, Inc., 2016.
Precaución: Estas citas no son 100% exactas.