BibTeX:
@incollection{BahyyihKhnum1982,
  author = {Bahíyyih Khánum},
  title = {Thoughts Must Be Focused on One Centre},
  booktitle = {Bahíyyih Khánum},
  year = {1982},
  url = {https://www.gutenberg.org/cache/epub/19242/pg19242-images.html},
}

APA:
Bahíyyih Khánum. (1982). Thoughts Must Be Focused on One Centre. In *Bahíyyih Khánum*.

MLA:
Bahíyyih Khánum. "Thoughts Must Be Focused on One Centre." *Bahíyyih Khánum*, 1982.

Chicago:
Bahíyyih Khánum. "Thoughts Must Be Focused on One Centre." In *Bahíyyih Khánum*, 1982.