BibTeX:
@incollection{Various,
  author = {Various},
  title = {A Picture in a Shop Window},
  booktitle = {Baha'i Stories for Children},
  url = {https://bahaistoriesforchildren.blogspot.com/2015/11/the-little-girl-who-saw-abdul-baha.html},
}

APA:
Various. A Picture in a Shop Window. In *Baha'i Stories for Children*.

MLA:
Various. "A Picture in a Shop Window." *Baha'i Stories for Children*, n.d..

Chicago:
Various. "A Picture in a Shop Window." In *Baha'i Stories for Children*, n.d..