https://digital.katalog.queersearch.org/s/katalog/item/43666, “Wise Parenthood: The Treatise on Birth Control for Married People: A Practical Sequel to "Married Love"”, https://digital.katalog.queersearch.org/s/katalog/item/49910, QueerSearch, accessed 1. Mai 2025, https://digital.katalog.queersearch.org/s/katalog/item/26656