APA

Heilbroner (Robert L), . (1972). The Worldly Philosophers. : .

Chicago

Heilbroner (Robert L), . 1972. The Worldly Philosophers. : .

Harvard

Heilbroner (Robert L), . (1972). The Worldly Philosophers. : .

MLA

Heilbroner (Robert L), . The Worldly Philosophers. : . 1972.