Williams, George2007Williams , G 2007 , ' Achieving open skies ' , Default journal .1646-3730Revista Lusófona de Ciências AeronáuticasTypes of Air Transport Trading Agreements: - Bilateral - "Open Skies" - Plurilateral - Multilateralapplication/pdfengopenAccessTRANSPORTES AÉREOSCOMPANHIAS AÉREASINDÚSTRIA AÉREAAIR TRANSPORTAIRLINESAIRLINE INDUSTRYAchieving open skies