Leonid A. Gavrilov & Natalia S. Gavrilova (1991), New York: Harwood Academic Publisher, ISBN 3-7186-4983-7* "Brain Boosters.
Leonid A. Gavrilov & Natalia S. Gavrilova (1991), New York: Harwood Academic Publisher, ISBN 3-7186-4983-7* "Brain Boosters.