BibTeX:
@incollection{BahChronicleseditors,
  author = {Bahá'í Chronicles editors},
  title = {The Brother Who Stayed},
  booktitle = {Bahá'í Chronicles},
  url = {https://bahaichronicles.org/his-eminence-kalim-mirza-musa/},
}

APA:
Bahá'í Chronicles editors. The Brother Who Stayed. In *Bahá'í Chronicles*.

MLA:
Bahá'í Chronicles editors. "The Brother Who Stayed." *Bahá'í Chronicles*, n.d..

Chicago:
Bahá'í Chronicles editors. "The Brother Who Stayed." In *Bahá'í Chronicles*, n.d..