00722nam a2200181 4500 1/22438 020606s1997 lu n001 0 eng 9282799751 23790 KET 629.136'6 VAL Validation process for users' requirements in air traffic operations Luxembourg : Office for Official Publications of the European Communities, 1997 52 σ.: 30 εκ. Transport research. APAS. Air transport ; Air traffic control European Union countries Evaluation. European Commission. Transport research. APAS. Air transport. INST UNIPILB KET 20050823 KET 629.136'6 VAL 00145816 00145816 LOAN 0 1