APA

Messinger R., Vallis E., . (1977). Machine placement of concrete ditches, barrrier walls, and curbs. : IRF world meeting 8. Session D.

Chicago

Messinger RD, Vallis ECM, . 1977. Machine placement of concrete ditches, barrrier walls, and curbs. : IRF world meeting 8. Session D.

Harvard

Messinger R., Vallis E., . (1977). Machine placement of concrete ditches, barrrier walls, and curbs. : IRF world meeting 8. Session D.

MLA

Messinger RD, Vallis ECM, . Machine placement of concrete ditches, barrrier walls, and curbs. : IRF world meeting 8. Session D. 1977.