EN ­ 1989 ­ 144 pp.; 21.0 χ 29.7 cm: softcover; 420 e
Α.; Soulas, S.; Ccdefop ­European Centre for the Development of Vocational Training EN/FR ­ 1988 ­ 250 pp.; 21.0 χ 29.7 cm: softcovcr; 600 g HX-52-88-259-2A-C ISBN 92-825-8160-8: ECU 5 FR :; 94 ­ 219