Hedberg H. Hollis. (1961). Part 25: International Subcommission on Stratigraphic Terminology. Stratigraphic Classification and Terminology; International Geological Congress. Report of the Twenty- First Session. Norden Denmark. Finland. Iceland. Norway. Sweden 1960. 1961.
Style de citation Chicago (17e éd.)Hedberg H. Hollis. Part 25: International Subcommission on Stratigraphic Terminology. Stratigraphic Classification and Terminology; International Geological Congress. Report of the Twenty- First Session. Norden Denmark. Finland. Iceland. Norway. Sweden 1960. 1961, 1961.
Style de citation MLA (9e éd.)Hedberg H. Hollis. Part 25: International Subcommission on Stratigraphic Terminology. Stratigraphic Classification and Terminology; International Geological Congress. Report of the Twenty- First Session. Norden Denmark. Finland. Iceland. Norway. Sweden 1960. 1961, 1961.