SAI AS/NZS 4968.1
SA ASNZS 49681 2003-JUL-11 Heavy road vehclesMechancal couplng between artculated vehcle combnatons Part 1 Desgn crtera and selecton requrements for ffth wheel kngpn and assocated equpment-Replaces AS 1771 AS 1773 AS 2175 and AS 4235