LEFFINGWELL W H. (1982). TEXTBOOK OF OFFICE MANAGEMENT (3RD.). TATA MCGRAW-HILL PUBLISHING COMPANY LIMITED.
Lua i Stíl Chicago (17ú heag.)LEFFINGWELL W H. TEXTBOOK OF OFFICE MANAGEMENT. 3RD. NEW DELHI: TATA MCGRAW-HILL PUBLISHING COMPANY LIMITED, 1982.
Lua MLA (9ú heag.)LEFFINGWELL W H. TEXTBOOK OF OFFICE MANAGEMENT. 3RD. TATA MCGRAW-HILL PUBLISHING COMPANY LIMITED, 1982.
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