Exman, E. (1967). The house of Harper: One hundred and fifty years of publishing. Harper & Row.
Lua i Stíl Chicago (17ú heag.)Exman, Eugene. The House of Harper: One Hundred and Fifty Years of Publishing. New York [u.a.]: Harper & Row, 1967.
Lua MLA (8ú heag.)Exman, Eugene. The House of Harper: One Hundred and Fifty Years of Publishing. Harper & Row, 1967.
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