Margaret Sanger, Michael W. Perry, H. G. Wells (2003). “The Pivot of Civilization in Historical Perspective: The Birth Control Classic”, p.345, Inkling Books
Margaret Sanger, Michael W. Perry, H. G. Wells (2003). “The Pivot of Civilization in Historical Perspective: The Birth Control Classic”, p.40, Inkling Books
Margaret Sanger (2016). “The Selected Papers of Margaret Sanger, Volume 4: Round the World for Birth Control, 1920-1966”, p.50, University of Illinois Press
Margaret Sanger, Michael W. Perry, H. G. Wells (2003). “The Pivot of Civilization in Historical Perspective: The Birth Control Classic”, p.338, Inkling Books