Kraus, E. H., & Slawson, C. B. (1947). Gems & gem materials: Edward H. Kraus (5th ed.). McGraw-Hill.
Dyfyniad Arddull ChicagoKraus, Edward H., and Chester Baker Slawson. Gems & Gem Materials: Edward H. Kraus. 5th ed. New York: McGraw-Hill, 1947.
Dyfyniad MLAKraus, Edward H., and Chester Baker Slawson. Gems & Gem Materials: Edward H. Kraus. 5th ed. McGraw-Hill, 1947.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.