Gaya APA

Harmer, G, R., N., C, E. (1970). Scotts standard postage stamp catalogue : Gordon R. Harmer . Omaha: Scott Publishing Co..

Gaya MLA

Harmer, Gordon, R.., N., Costales, Eugene. "Scotts standard postage stamp catalogue : Gordon R. Harmer". Omaha: Scott Publishing Co., 1970. Koleksi Lama.