BibTeX:
@incollection{Various,
  author = {Various},
  title = {The master Nan-in had a visitor who came to inquire about Zen},
  booktitle = {bahaistories.com archive},
  url = {https://bahaistories.com/subject/detachment},
}

APA:
Various. The master Nan-in had a visitor who came to inquire about Zen. In *bahaistories.com archive*.

MLA:
Various. "The master Nan-in had a visitor who came to inquire about Zen." *bahaistories.com archive*, n.d..

Chicago:
Various. "The master Nan-in had a visitor who came to inquire about Zen." In *bahaistories.com archive*, n.d..