References Hyperboloid

wilhelm blaschke (1948) analytische geometrie, kapital v: quadriken , wolfenbutteler verlagsanstalt.
david a. brannan, m. f. esplen, & jeremy j gray (1999) geometry, pp. 39–41 cambridge university press.
h. s. m. coxeter (1961) introduction geometry, p. 130, john wiley & sons.