BibTeX:
@incollection{AbdulBaha,
  author = {'Abdu'l-Baha},
  title = {The Babis' Angel Gabriel},
  booktitle = {Memorials of the Faithful},
}

APA:
'Abdu'l-Baha. The Babis' Angel Gabriel. In *Memorials of the Faithful*.

MLA:
'Abdu'l-Baha. "The Babis' Angel Gabriel." *Memorials of the Faithful*, n.d..

Chicago:
'Abdu'l-Baha. "The Babis' Angel Gabriel." In *Memorials of the Faithful*, n.d..