BibTeX:
@incollection{Various,
  author = {Various},
  title = {A Fragment from Máh-Kú},
  booktitle = {bahaistories.com archive},
  url = {https://bahaistories.com/subject/shrine-bab},
}

APA:
Various. A Fragment from Máh-Kú. In *bahaistories.com archive*.

MLA:
Various. "A Fragment from Máh-Kú." *bahaistories.com archive*, n.d..

Chicago:
Various. "A Fragment from Máh-Kú." In *bahaistories.com archive*, n.d..