1. D. W. Kessler, "Permeability of Stone," Bur. Stand., Tech. Paper, No. 305.
2. P. W. Ketchum, A. E. R. Westman, and R. K. Hursh, "The Measurement of the Permeability of Ceramic Bodies." Univ. Ill. Bull., Circ., No. 14.
3. Relation between water permeability and water absorbtion of concrete