@inbook{Ingersoll1899whatreligion,
  author    = {Ingersoll, Robert G.},
  title     = {What Is Religion?},
  booktitle = {The Works of Robert G. Ingersoll, Dresden Edition},
  publisher = {C. P. Farrell},
  address   = {New York},
  volume    = {4},
  year      = {1899},
  url       = {https://thegreatagnostic.com/works/what-is-religion/},
  note      = {Public domain. Dresden Edition identifier: dresden:vol-4:what-is-religion}
}