Columbia subject headings:
Harvard subject headings:
Post roads--Europe--Early works to 1800.
Post roads--Spain--Early works to 1800.
Postal rates--Europe--Early works to 1800.
Postal service--Europe--Early works to 1800.
Postal service--Law and legislation--Spain--Early works to 1800.
Postal service--Spain--Early works to 1800.
Princeton subject headings:
Post roads--Europe--Early works to 1800.
Post roads--Spain--Early works to 1800.
Postal service--Europe--Early works to 1800.
Postal service--Europe--Rates--Early works to 1800.
Postal service--Law and legislation--Spain--Early works to 1800.
Postal service--Spain--Early works to 1800.