BibTeX:
@incollection{Various,
  author = {Various},
  title = {Warden of the Báb witnesses a miracle},
  booktitle = {Baha'i Stories for Children},
  url = {https://bahaistoriesforchildren.blogspot.com/2021/10/warden-of-bab-witnesses-miracle.html},
}

APA:
Various. Warden of the Báb witnesses a miracle. In *Baha'i Stories for Children*.

MLA:
Various. "Warden of the Báb witnesses a miracle." *Baha'i Stories for Children*, n.d..

Chicago:
Various. "Warden of the Báb witnesses a miracle." In *Baha'i Stories for Children*, n.d..