A working paper is a draft or an early version of a piece of writing, usually one that either has been or will be submitted for publication. Working papers submitted for publication can also be called prepublication or preprint versions, or by the term gray literature. You should either indicate that the source is a working paper in your prose or use the optional-element slot at the end of the entry to do so. The following sentence and works-cited-list entry provide an example of how to cite a working paper that is available in an online archive:

In a working paper published in CORE, an open-access repository for humanities research, Erin Rose Glass and Micah Vandegrift argue that “[c]onnecting to the public is a key part of the mission of higher education.”

Work Cited

Glass, Erin Rose, and Micah Vandegrift. “Public Scholarship in Practice and Philosophy.” CORE, 2018, dx.doi.org/10.17613/g64d-gd16. PDF download.

The following provides an example of how you would use the optional-element slot at the end of the entry to indicate that the source is a working paper (if, say, you did not mention it in your prose):  

Work Cited

Conover, Kellam. “Rereading the Death of Turnus: Ritual, Time and Poetics in the Aeneid.” Princeton/Stanford Working Papers in Classics,  www.princeton.edu/~pswpc/papers/authorAL/conover/conover.hml. Working paper.