If an author’s last name is not provided in the source you are consulting, you may opt to follow the guidance provided in section 5.122 of the MLA Handbook: When a source does not include certain facts, such as the full name of the author, “writers, especially scholars who possess working familiarity with their sources, may be able to supply missing information.” In such instances, “[u]se square brackets to show that the information was supplied.” For instance:
[Smith], Thomas. On the Presence and Absence of Surnames. No-Name Press, 1985.
If you are not sure that the supplied information is correct, include a question mark in square brackets:
[Smith?], Thomas. On the Presence and Absence of Surnames. No-Name Press, 1985.
If you do not know the author’s last name and thus are unable to supply it, present the name as it appears in the source. (As noted in section 5.11 of the handbook, the names of authors who lack surnames are not reversed in the Author element in works-cited-list entries.) For example:
Thomas. On the Presence and Absence of Surnames. No-Name Press, 1985.
Work Cited
MLA Handbook. 9th ed., Modern Language Association of America, 2021. MLA Handbook Plus, 2021, mlahandbookplus.org/.