Gaya APA

Libby, J, R., Perkins, N, D. (1976). Modern prestressed concrete : Highway Bridge superstructures design principles and contruction mathods . California: Grantville Publishing.

Gaya MLA

Libby, James, R.., Perkins, Norman, D.. "Modern prestressed concrete : Highway Bridge superstructures design principles and contruction mathods". California: Grantville Publishing, 1976. Text.