Internationalising vocational education and training in Europe, prelude to an overdue dabate : a discussion paper [documento eletrónico] / Compil. Jorn Sogaard and Norbert Wollschläger on the occasion of the Conference on Internationalising Vocational Education and Training in Europe, Thessaloniki, 25-27 May 2000 ; published European Centre for the Development of Vocational Training