1. Aicaraz, A., 1969,Is Taal Volcano Drawing Closer to Another Eruptive Activity? The COMVOL Letter, Vol. III No. 5 Sept.–Oct. 1969.
2. Beck, A. C., 1951,Volcanic Activity at Mt Ruapehu from August to December 1945. N.Z.J. Sci. Tech.,B 31 (5), p. 1–13.
3. Cowan, J., 1927,The Tongariro National Park, New Zealand. Tongariro National Park Board, Wellington, 156 pp.
4. Dawson, G. B., 1964,The Nature and Assessment of Heat Flow from Hydrothermal Areas. N.Z. Geol. Geophys.,7, p. 155–171.
5. Dibble, R. R., 1966,Seismic Recordings of Subterranean Volcanic Activity at Ruapehu During 1964. Bull. Volc.,29, p. 761.