APA

Walsh S. L., Gradstein F. M. & Ogg J. G.History, philosophy, and application of the Global Stratotype Section and Point (GSSP). : .

Chicago

Walsh Stephen L, Gradstein Felix M and Ogg Jim G.History, philosophy, and application of the Global Stratotype Section and Point (GSSP). : .

Harvard

Walsh S. L., Gradstein F. M. and Ogg J. G.History, philosophy, and application of the Global Stratotype Section and Point (GSSP). : .

MLA

Walsh Stephen L, Gradstein Felix M and Ogg Jim G.: . .