Columbia subject headings:
Harbors--Illinois--Periodicals.
Harbors--Indiana--Periodicals.
Shipping--Illinois--Illinois River--Periodicals.
Shipping--Michigan, Lake--Periodicals.
Harvard subject headings:
Harbors--Illinois--Periodicals.
Harbors--Indiana--Periodicals.
Shipping--Illinois--Illinois River--Periodicals.
Shipping--Michigan, Lake--Periodicals.
Princeton subject headings:
Harbors--Illinois--Periodicals.
Harbors--Indiana--Periodicals.
Shipping--Illinois--Illinois River--Periodicals.
Shipping--Michigan, Lake--Periodicals.