Douglas, H. E. (1975). Perfection The impossible possibility. Southern.
Cita Chicago (17th ed.)Douglas, Herbert E. Perfection The Impossible Possibility. Southern, 1975.
Cita MLA (9th ed.)Douglas, Herbert E. Perfection The Impossible Possibility. Southern, 1975.
Atenció: Aquestes cites poden no estar 100% correctes.