Columbia subject headings:
Hecker, Isaac Thomas, 1819-1888.
Vatican Council (1st : 1869-1870 : Basilica di San Pietro in Vaticano)
Harvard subject headings:
Hecker, Isaac Thomas, 1819-1888
Vatican Council (1st : 1869-1870 : Basilica di San Pietro in Vaticano)
Princeton subject headings:
Hecker, Isaac Thomas, 1819-1888.
Vatican Council (1st : 1869-1870)