BibTeX:
@incollection{ShoghiEffendi1941,
  author = {Shoghi Effendi},
  title = {A Tempest Sweeping the Earth: Shoghi Effendi on the Modern Crisis},
  booktitle = {The Promised Day Is Come},
  year = {1941},
  publisher = {Bahá'í Publishing Trust},
}

APA:
Shoghi Effendi. (1941). A Tempest Sweeping the Earth: Shoghi Effendi on the Modern Crisis. In *The Promised Day Is Come*. Bahá'í Publishing Trust.

MLA:
Shoghi Effendi. "A Tempest Sweeping the Earth: Shoghi Effendi on the Modern Crisis." *The Promised Day Is Come*, Bahá'í Publishing Trust, 1941.

Chicago:
Shoghi Effendi. "A Tempest Sweeping the Earth: Shoghi Effendi on the Modern Crisis." In *The Promised Day Is Come*, Bahá'í Publishing Trust, 1941.