O'Connor, R. (1971). The oil barons: Men of greed and grandeur (3. print.). Little, Brown.
Citazione stile Chigago Style (17a edizione)O'Connor, Richard. The Oil Barons: Men of Greed and Grandeur. 3. print. Boston [u.a.]: Little, Brown, 1971.
Citatione MLA (8a ed.)O'Connor, Richard. The Oil Barons: Men of Greed and Grandeur. 3. print. Little, Brown, 1971.
Attenzione: Queste citazioni potrebbero non essere precise al 100%.