MLA

Collins, Charles Allston, 1828-1873. The mystery of Edwin Drood by Charles Dickens ... reduced facsimilie [sic] of cover of orginal parts, drawn by Charles Alston Collins.. 1920?]. https://collections.library.yale.edu/catalog/15809975.

APA, 6th edition

Collins, Charles Allston, 1828-1873. (1920?])[The mystery of Edwin Drood by Charles Dickens ... reduced facsimilie [sic] of cover of orginal parts, drawn by Charles Alston Collins.]. https://collections.library.yale.edu/catalog/15809975.