BibTeX:
@incollection{Various,
  author = {Various},
  title = {The Guardian's Heart Was Like a Mirror},
  booktitle = {bahaistories.com archive},
  url = {https://bahaistories.com/subject/shoghi-effendi},
}

APA:
Various. The Guardian's Heart Was Like a Mirror. In *bahaistories.com archive*.

MLA:
Various. "The Guardian's Heart Was Like a Mirror." *bahaistories.com archive*, n.d..

Chicago:
Various. "The Guardian's Heart Was Like a Mirror." In *bahaistories.com archive*, n.d..