Columbia subject headings:
Old Catholic Church in America--Bibliography.
Old Catholic Church--Bibliography.
Polish National Catholic Church of America--Bibliography.
Harvard subject headings:
Old Catholic Church--Archives--Indexes.
Old Catholic Church--History--Sources--Indexes.
Old Catholic Church--Periodicals--Indexes.
Polish National Catholic Church of America--Archives--Indexes.
Polish National Catholic Church of America--History--Sources--Indexes.
Polish National Catholic Church of America--Periodicals--Indexes.
Princeton subject headings:
Independent Catholic churches--United States--Bibliography.
Old Catholic Church--United States--Bibliography.
Polish National Catholic Church of America--Bibliography.