Columbia subject headings:
Harvard subject headings:
Astronomers--Italy--Correspondence.
Astronomy--Italy--History.
Secchi, Angelo, 1818-1878--Correspondence.
Tacchini, P. (Pietro), 1838-1905--Correspondence.
Princeton subject headings:
Astronomers--Italy--Correspondence.
Astronomy--Italy--History--19th century--Sources.
Astrophysicists--Italy--Correspondence.
Astrophysics--Italy--History--19th century--Sources.
Secchi, Angelo, 1818-1878--Correspondence.
Tacchini, P. (Pietro), 1838-1905--Correspondence.