1. O'NEILL,B., Elementary Differential Geometry, Academic Press, New York, 1966.
2. O'NEILL,B., Semi-Riemannian Geometry, Academic Press, New York, London, 1983.
3. SPIVAK,M., A Comprehensive Introduction to Differential Geometry, Vol. III, Publish or Perish, Berkley, 1975.
4. TAKEUCHI,N. and TAMURA,M., A surface which contains helical geodesics, Bull. Tokyo Gakugei Univ.(4) 42 (1990), 15?18.
5. TAMURA,M., Surfaces which contain helical geodesics, Geometriae Dedicata. 42 (1992), 311?315.