APA استشهاد

Lewis, W. (1969). Principles of Economic Planning (3rd Ed.). George Allen & Unwin.

استشهاد بنمط شيكاغو

Lewis, W.Arthur. Principles of Economic Planning. 3rd Ed. Bombay: George Allen & Unwin, 1969.

MLA استشهاد

Lewis, W.Arthur. Principles of Economic Planning. 3rd Ed. George Allen & Unwin, 1969.