BibTeX:
@incollection{Various,
  author = {Various},
  title = {‘Abdu’l-Bahá at Howard University},
  booktitle = {bahaistories.com archive},
  url = {https://bahaistories.com/subject/race-unity},
}

APA:
Various. ‘Abdu’l-Bahá at Howard University. In *bahaistories.com archive*.

MLA:
Various. "‘Abdu’l-Bahá at Howard University." *bahaistories.com archive*, n.d..

Chicago:
Various. "‘Abdu’l-Bahá at Howard University." In *bahaistories.com archive*, n.d..