APA aipamena

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

Chicago Style aipamena

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

MLA aipamena

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

Kontuz: berrikusi erreferentzia hauek erabili aurretik.