Heuduck, P. (1941). Post Office receipt, October 3, 1941. Saint Louis University Libraries Digitization Center.
Chicago-viite (17. p.)Heuduck, Paul. Post Office Receipt, October 3, 1941. Saint Louis University Libraries Digitization Center, 1941.
MLA-viite (8. p.)Heuduck, Paul. Post Office Receipt, October 3, 1941. Saint Louis University Libraries Digitization Center, 1941.
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