BibTeX:
@incollection{Various,
  author = {Various},
  title = {Arty from the Arctic},
  booktitle = {Baha'i Stories for Children},
  url = {https://bahaistoriesforchildren.blogspot.com/2017/03/arty-from-arctic.html},
}

APA:
Various. Arty from the Arctic. In *Baha'i Stories for Children*.

MLA:
Various. "Arty from the Arctic." *Baha'i Stories for Children*, n.d..

Chicago:
Various. "Arty from the Arctic." In *Baha'i Stories for Children*, n.d..