International Sub commission on Stratigraphic Classification [Report No. 7b; editor H. D. Hedberg]: Summary of an International Guide to Stratigraphic Classification, Terminology, and Usage. Lethaia, Vol. 5, pp. 297–323. Oslo, July 15th, 1972.
Six published reports (and some 40 circulars) of the International Sub commission on Stratigraphic Classification (ISSC) constitute the principal bases for the initial edition of an International Guide to Stratigraphic Classification, Terminology, and Usage. The published reports on Lithostratigraphic Units, Biostratigraphic Units, Chronostratigraphic Units, and Stratotypes are advance chapters of the Guide. The following Summary, which with the preceding Introduction will form the first chapter of the completed Guide, provides a concise and condensed statement of principles, definitions, and proposed rules, which are elaborated in more detail in the published reports and individual chapters of the Guide.