1. ASTM (American Society for Testing and Materials). (2016) Standard Test Method for Slake Durability of Shales and Other Similar Weak Rocks ASTM/D4644-16.
2. ASTM (American Society for Testing and Materials). (2016) Standard Test Method for Splitting Tensile Strength of Intact Rock Core Specimens ASTM/D3967-16.
3. ASTM (American Society for Testing and Materials). (1995) Standard Test Method for Unconfined Compressive Strength of Intact Rock Core Specimens ASTM/D2938-95.
4. JGS (Japanese Geotechnical Society Hokkaido Branch) Research Committee on Frost Damage of Slopes and Countermeasures. (2016) Guidelines for Frost Damage of Slope and Countermeasures. (in Japanese)
5. JMA (Japan Meteorological Agency) "Search for Historical Weather Data" (Aug. 31 2019).