BibTeX:
@incollection{Various,
  author = {Various},
  title = {The Rule of Thumb},
  booktitle = {Baha'i Stories for Children},
  url = {https://bahaistoriesforchildren.blogspot.com/2014/11/the-rule-of-thumb.html},
}

APA:
Various. The Rule of Thumb. In *Baha'i Stories for Children*.

MLA:
Various. "The Rule of Thumb." *Baha'i Stories for Children*, n.d..

Chicago:
Various. "The Rule of Thumb." In *Baha'i Stories for Children*, n.d..