The following references appear in the Marlowe Census, including the initials of scholars who have provided information about particular copies.
DEEP // Alan B. Farmer and Zachary Lesser, DEEP: Database of Early English Playbooks
ESTC // English Short Title Catalogue
Greg // W.W. Greg, A Bibliography of the English Printed Drama to the Restoration, 4 vols. (London: Bibliographical Society, 1939-59)
RC // Rob Carson
STC // A Short-Title Catalogue of Books Printed in England, Scotland, & Ireland and of English Books Printed Abroad, 1475-1640, 2nd edition, ed. A.W. Pollard, G. R. Redgrave, W. A. Jackson, F. S. Ferguson, and Katharine F. Pantzer, 3 vols. (London: Bibliographical Society, 1976-91)
Wing // Donald Wing, ed., Short-Title Catalogue of Books Printed in England, Scotland, Ireland, Wales, and British America, and of English Books Printed in Other Countries, 1641-1700, 2nd edition, 4 vols. (New York: MLA, 1972-98).