Olson, Gerald W. “Criteria for Making and Interpreting a Soil Profile Description: A Complication of the Official USDA Procedure and Nomenclature for Describing Soils”. Bulletin (Kansas Geological Survey), no. 212 (January 1, 1976): 1–48. Accessed August 24, 2024. https://journals.ku.edu/kgsbulletin/article/view/22262.