Columbia subject headings:
Ashby, Thomas, 1874-1931--Art collections--Catalogs.
Drawing--19th century--Catalogs.
Drawing--Private collections--Vatican City--Catalogs.
Fondo Ashby (Biblioteca apostolica vaticana)--Catalogs.
Harvard subject headings:
Ashby, Thomas, 1874-1931--Art collections.
Biblioteca apostolica vaticana--Catalogs.
Drawing, European--19th century--Catalogs.
Princeton subject headings:
Ashby, Thomas, 1874-1931--Art collections--Catalogs.
Catalogs.
Drawing--19th century--Catalogs.
Drawing--Private collections--Vatican City--Catalogs.
Fondo Ashby (Biblioteca apostolica vaticana)--Catalogs.