Columbia subject headings:
Communication and traffic--Oklahoma--Periodicals.
Corporations--Oklahoma--Periodicals.
Public utilities--Oklahoma--Periodicals.
Railroads--Oklahoma--Periodicals.
Harvard subject headings:
Communication and traffic--Oklahoma--Periodicals.
Corporations--Oklahoma--Periodicals.
Public utilities--Law and legislation--Oklahoma--Periodicals.
Railroads--Oklahoma--Periodicals.
Princeton subject headings:
Communication and traffic--Oklahoma--Periodicals.
Corporations--Oklahoma--Periodicals.
Periodicals.
Public utilities--Oklahoma--Periodicals.
Railroads--Oklahoma--Periodicals.