BibTeX:
@incollection{Various,
  author = {Various},
  title = {The march to Constantinople occupied four months},
  booktitle = {bahaistories.com archive},
  url = {https://bahaistories.com/subject/bahaullah-exile},
}

APA:
Various. The march to Constantinople occupied four months. In *bahaistories.com archive*.

MLA:
Various. "The march to Constantinople occupied four months." *bahaistories.com archive*, n.d..

Chicago:
Various. "The march to Constantinople occupied four months." In *bahaistories.com archive*, n.d..