1. ASTM (2002) Standard test method for determining rock quality designation (RQD) of rock core. ASTM standard D6032–02. ASTM International, West Conshohocken
2. Bar N, Barton N (2017) The Q-slope method for rock slope engineering. Rock Mech Rock Eng 50:3307–3322
3. Barton N and Bar N, Introducing the Q-slope method and its intended use within civil and mining engineering projects. In ISRM Regional Symposium-EUROCK 2015. One Petro.
4. Bieniawski ZT (1989) Engineering rock mass classification. Wiley, Chichester
5. Bieniawski ZT, Rock mass classification in rock engineering. In: Proceeding of the Symposium on Exploration for Rock Engineering (ed. ZT Bieniawski) 1976; pp. 97–106.