BibTeX:
@incollection{ShoghiEffendi1982,
  author = {Shoghi Effendi},
  title = {The Greatest Holy Leaf's Immortal Spirit},
  booktitle = {Bahíyyih Khánum},
  year = {1982},
  pages = {Part III, no. 3},
  url = {https://www.gutenberg.org/cache/epub/19242/pg19242-images.html},
}

APA:
Shoghi Effendi. (1982). The Greatest Holy Leaf's Immortal Spirit. In *Bahíyyih Khánum* (p. Part III, no. 3).

MLA:
Shoghi Effendi. "The Greatest Holy Leaf's Immortal Spirit." *Bahíyyih Khánum*, 1982, p. Part III, no. 3.

Chicago:
Shoghi Effendi. "The Greatest Holy Leaf's Immortal Spirit." In *Bahíyyih Khánum*, Part III, no. 3. 1982.