If a source is written by an author who is known only by initials, you have several options.
Treat the Initials as a Unit
One option is to treat the initials as a unit. You would use the initials in your prose or in your in-text citation and list the entry under the first initial in your works-cited list entry:
“It is now received a general opinion that the good will of parents is required . . .” (T. E. 53).
T. E. The Law’s Resolutions of Women’s Rights; or The Law’s Provision for Women. London, 1632.
You should choose this option if you have no way of knowing whether the initials represent a first and last name.
Treat the Initials as Representing a First and Last Name
Another option is to treat the initials as representing a first and last name. In this case, use the initials in your prose or in your in-text citation and invert the initials in the works-cited-list entry. List the entry under the last initial.
Among other anti-Pamelists is J– W–, author of Pamela; or, The Fair Imposter.
W–, J–, esquire. Pamela; or, The Fair Imposter: A Poem in Five Cantas. Dublin, 1743.
Use this option if you are sure that the initials stand for a first and last name or if it’s conventional to treat them thus. Here the dashes after the initials, which are present in the source, and the use of “esquire” suggest that the initials refer to a first and last name. An eighteenth-century scholar would be aware that names are conventionally represented in this manner in works from the 1700s.
Replace the Initials with the Full Name
If you know or can find the full name of the person represented by the initials, you should replace the initials with the full name. For example, the author of the preface to the MLA’s publication Approaches to Teaching the Novels of Samuel Richardson is listed as “L. Z.” Since the book is edited in part by Lisa Zunshine, if you cite the preface in your works-cited list, you would provide Lisa Zunshine’s full name:
Zunshine, Lisa. Preface. Approaches to Teaching the Novels of Samuel Richardson, edited by Zunshine and Jocelyn Harris, Modern Language Association of America, 2006, pp. xi-xiii.
Although a student would not be expected to look outside the source to discover what the initials stand for, a scholar might look for the full name in archival materials or might simply know that a particular person from the period is known by the initials.
Examples adapted from Mary Beth Rose, “A Voyage on a Dangerous Sea: Marriage as Heroism in Early Modern English Prose,” Teaching Early Modern English Prose, edited by Susannah Brietz Monta and Margaret W. Ferguson, Modern Language Association of America, 2010, pp. 143–53; Felicity A. Nussbaum, “Naughty Pamela’s ‘Sweet Confusion,’” Approaches to Teaching the Novels of Samuel Richardson, edited by Lisa Zunshine and Jocelyn Harris, Modern Language Association of America, 2006, pp. 63–69.