1. A seismic investigation of the Witwatersrand earth tremors;Gane;Bull. seism. Soc. Am.,1946
2. Focal depths of Witwatersrand tremors;Gane;Bull. seism. Soc. Am.,1952
3. The seismic location of rockbursts;Cook,1963
4. Relationship of mine tremors to induced stresses and to rock properties in the focal region;McGarr;Bull. seism. Soc. Am.,1975
5. Elementary Seismology;Richter,1958