APA (7th ed.) Citation

Gedat, G. A. (1971). They built for eternity. Books for Libraries Press.

Chicago Style (17th ed.) Citation

Gedat, Gustav Adolf. They Built for Eternity. Freeport, N.Y.: Books for Libraries Press, 1971.

MLA (9th ed.) Citation

Gedat, Gustav Adolf. They Built for Eternity. Books for Libraries Press, 1971.