ISRM (1985): Suggested method for determining point load strength. International Journal of Rock Mechanics and Mining Sciences and Geomechanical Abstract, 22(2), 51-60.
ASTM D5731-16, Standard Test Method for Determination of the Point Load Strength Index of Rock and Application to Rock Strength Classifications, ASTM International, West Conshohocken, PA, 2016, www.astm.org