Council Directive 77/311/EEC of 29 March 1977 on the approximation of the laws of the Member States relating to the driver-perceived noise level of wheeled agricultural or forestry tractors
Direktiva Sveta 77/311/EGS z dne 29. marca 1977 o približevanju zakonodaje držav članic o ravni hrupa, ki ga zaznavajo vozniki kmetijskih ali gozdarskih traktorjev na kolesih