BibTeX:
@incollection{Various,
  author = {Various},
  title = {Louis Gregory’s vision and ‘Abdu’l-Baha’s interpretation},
  booktitle = {Baha'i Stories Blog},
  url = {https://bahaistories.blogspot.com/2014/12/louis-gregorys-vision-and-abdul-bahas.html},
}

APA:
Various. Louis Gregory’s vision and ‘Abdu’l-Baha’s interpretation. In *Baha'i Stories Blog*.

MLA:
Various. "Louis Gregory’s vision and ‘Abdu’l-Baha’s interpretation." *Baha'i Stories Blog*, n.d..

Chicago:
Various. "Louis Gregory’s vision and ‘Abdu’l-Baha’s interpretation." In *Baha'i Stories Blog*, n.d..