Fries, James F. Vitality and againg : implications of the rectangular curve / James F. Fries, Lawrence M. Crapo - San Francisco : W.H. Freeman , 1981 - xii, 172p. : ill. ; 24 cm. Includes index ISBN: 071671308X Subjects--Topical Terms: VejezLongevidadVitalidad LC Class. No.: QP 86 / F 73 1981