Cita APA (7a ed.)

Helpman, E. (1987). Imperfect competition and international trade: Evidence from fourteen industrial countries. [s.n.].

Cita Chicago Style (17a ed.)

Helpman, Elhanan. Imperfect Competition and International Trade: Evidence from Fourteen Industrial Countries. [S.l.]: [s.n.], 1987.

Cita MLA (9a ed.)

Helpman, Elhanan. Imperfect Competition and International Trade: Evidence from Fourteen Industrial Countries. [s.n.], 1987.