Gaya APA

al, E., Wibisono,Widyastuti, . (1999). Proceeding of International Conference on occupational health and safety in the informal sector . Jakarta: Ministry of Health and safety of Indonesia.

Gaya MLA

al, Et., Wibisono,Widyastuti, . "Proceeding of International Conference on occupational health and safety in the informal sector". Jakarta: Ministry of Health and safety of Indonesia, 1999. print.