LIFE SYMBOLS AS RELATED TO SEX SYMBOLISM : … ORIGIN AND SIGNIFICANCE … THE CIRCLE, THE SERPENT, THE TRIANGLE, THE TREE OF LIFE, THE SWASTIKA, AND OTHER SOLAR EMBLEMS… BY ELISABETH GOLDSMITH (1924)
NATURE’S SECRETS REVEALED : SCIENTIFIC KNOWLEDGE OF THE LAWS OF SEX LIFE AND HEREDITY OR EUGENICS BY THOMAS W. SHANNON (1917)