Wolff, H. (1989). Philippine directory of occupational health and safety. Edith T. Flores & Hans-Juergen Wolff.
Chicago Style aipamenaWolff, Hans-Juergen. Philippine Directory of Occupational Health and Safety. Manila: Edith T. Flores & Hans-Juergen Wolff, 1989.
MLA aipamenaWolff, Hans-Juergen. Philippine Directory of Occupational Health and Safety. Edith T. Flores & Hans-Juergen Wolff, 1989.
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