Citazione Stile APA (7a Edizione)

Helmus, T. M., & Arnsdorf, V. E. (1984). The United States and its neighbors. Silver Burdett.

Citazione stile Chigago Style (17a edizione)

Helmus, Timothy M., e Val E. Arnsdorf. The United States and Its Neighbors. Morristown, NJ [u.a.]: Silver Burdett, 1984.

Citatione MLA (9a ed.)

Helmus, Timothy M., e Val E. Arnsdorf. The United States and Its Neighbors. Silver Burdett, 1984.