Skempton, A.W. (1953). "The Colloidal "Activity" of Clays"(PDF). International Society For Soil Mechanics and Geotechnical Engineering. Archived(PDF) from the original on 2021-10-02. Retrieved 2022-06-18.
Skempton, A.W. (1953). "The Colloidal "Activity" of Clays"(PDF). International Society For Soil Mechanics and Geotechnical Engineering. Archived(PDF) from the original on 2021-10-02. Retrieved 2022-06-18.