BibTeX:
@incollection{Various,
  author = {Various},
  title = {A Prayer for Mirza Ja'far},
  booktitle = {Baha'i Stories for Children},
  url = {https://bahaistoriesforchildren.blogspot.com/2014/11/a-prayer-for-mirza-jafar.html},
}

APA:
Various. A Prayer for Mirza Ja'far. In *Baha'i Stories for Children*.

MLA:
Various. "A Prayer for Mirza Ja'far." *Baha'i Stories for Children*, n.d..

Chicago:
Various. "A Prayer for Mirza Ja'far." In *Baha'i Stories for Children*, n.d..