García-Guinea, J., M. Lombardero, B. Roberts, J. Taboada, and A. Peto. 1998. “Mineralogy and Microstructure of Roofing Slate: Thermo-Optical Behaviour and Fissility”. Materiales De Construcción 48 (251):37-48. https://doi.org/10.3989/mc.1998.v48.i251.470.