Citazione Stile APA (7a Edizione)

KREBS, R. D., & WALKER, R. D. (1971). Highway materials. McGraw-Hill.

Citazione stile Chigago Style (17a edizione)

KREBS, Robert D., e Richard D. WALKER. Highway Materials. New York: McGraw-Hill, 1971.

Citatione MLA (9a ed.)

KREBS, Robert D., e Richard D. WALKER. Highway Materials. McGraw-Hill, 1971.