1. Local bulletin of earthquakes in the southern California region, 1 Jan. 1967 to 31 Dec. 1967;Allen,1968
2. Observations of nearby microearthquakes with ultrasensitive seismometers;Asada;J. Physics of the Earth,1957
3. Thermal energy from the earth's crust;Banwell,1963
4. World seismicity maps compiled from ESSA, Coast and Geodetic Survey, epicenter data, 1961–1967;Barazangi;Bull. Seism. Soc. Amer.,1969
5. Physical characteristics of natural heat resources in Iceland;Bodvarsson;Jökull,1961