Include a Digital Object Identifier (DOI) to an online journal article when possible.
If no DOI is available, include a URL without http:// or https://.
On a database, use the permanent link or permalink.
Include an at the end of a citation. Your professor requires it.
Abbreviate publishers' names, omitting business words (Co., Corp., Ltd., etc.).
Abbreviate the names of academic presses, for example replace University Press with UP.
See the MLA Handbook 9th Edition, page 172 for more guidance.