BibTeX:
@incollection{Various,
  author = {Various},
  title = {The Passing of Bahá'u'lláh at Bahjí},
  booktitle = {bahaistories.com archive},
  url = {https://bahaistories.com/subject/bahaullah-ascension},
}

APA:
Various. The Passing of Bahá'u'lláh at Bahjí. In *bahaistories.com archive*.

MLA:
Various. "The Passing of Bahá'u'lláh at Bahjí." *bahaistories.com archive*, n.d..

Chicago:
Various. "The Passing of Bahá'u'lláh at Bahjí." In *bahaistories.com archive*, n.d..