APA

National Productivity Board, . (1991). A tribute to the Singapore workforce. Singapore: National Productivity Board.

Chicago

National Productivity Board, . 1991. A tribute to the Singapore workforce. Singapore: National Productivity Board.

Harvard

National Productivity Board, . (1991). A tribute to the Singapore workforce. Singapore: National Productivity Board.

MLA

National Productivity Board, . A tribute to the Singapore workforce. Singapore: National Productivity Board. 1991.