BibTeX:
@incollection{Various,
  author = {Various},
  title = {Christmas Day in London, 1912},
  booktitle = {bahaistories.com archive},
  url = {https://bahaistories.com/subject/christmas},
}

APA:
Various. Christmas Day in London, 1912. In *bahaistories.com archive*.

MLA:
Various. "Christmas Day in London, 1912." *bahaistories.com archive*, n.d..

Chicago:
Various. "Christmas Day in London, 1912." In *bahaistories.com archive*, n.d..