Richberg, D. R. (1957). Labor union monopoly: A clear and present danger / by Donald R. Richberg (2. print.). Regnery.
Citazione stile Chigago Style (17a edizione)Richberg, Donald Randall. Labor Union Monopoly: A Clear and Present Danger / by Donald R. Richberg. 2. print. Chicago: Regnery, 1957.
Citatione MLA (8a ed.)Richberg, Donald Randall. Labor Union Monopoly: A Clear and Present Danger / by Donald R. Richberg. 2. print. Regnery, 1957.
Attenzione: Queste citazioni potrebbero non essere precise al 100%.