Columbia subject headings:
Incunabula.
Printing--History.
Type and type-founding.
Harvard subject headings:
Incunabula--Bibliography.
Incunabula.
Printing--History
Printing--History--Origin and antecedents
Type and type-founding
Type and type-founding--History--To 1500.
Princeton subject headings:
Incunabula.
Printing--History.
Type and type-founding.