Gaya APA

Mason, R, D., Lange, W, H. (1976). Prorammed learning aid for: using the metric system . Homewood Illinois: Richard D. Irwin.

Gaya MLA

Mason, Robert, D.., Lange, Walter, H.. "Prorammed learning aid for: using the metric system". Homewood Illinois: Richard D. Irwin, 1976. Printed Book.