Frailey, L. E. (1942). How to write better business letters. American Technical Society.
Lua i Stíl Chicago (17ú heag.)Frailey, L. E. How to Write Better Business Letters. Chicago: American Technical Society, 1942.
Lua MLA (8ú heag.)Frailey, L. E. How to Write Better Business Letters. American Technical Society, 1942.
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