1. ISO. Geotechnical investigation and testing—identification and classification of rock, Part 1: identification and description. ISO 14689-1:2003(E).
2. JGS. Method for engineering classification of rock mass. Designation: JGS 3811-2004.
3. Maeda H. What should we do, from now on, to be making progress on landslide science in the Hokkaido Branch of the Japan Landslide Society and the Hokkaido Landslide Society? In: 30-years-studies on landslides in Hokkaido (CD-DATA); 2008. p. 1–10. [in Japanese].
4. Relationship between cylinder (longitudinal) point load strength and uniaxial compression strength for smectite-bearing fine tuffs in a soft and semi-hard rock boundaly area: Example of the Upper Miocene Ikutawara Formation from the Ikutahara-Minami landslide area
5. Method of axial point load strength test for smectite-bearing rocks;Kohno;JSCE J Geotech Geoenviron Eng,2010