Judgment of the Court (First Chamber) of 27 May 2004 in Case C-285/02 (reference for a preliminary ruling from the Verwaltungsgericht Minden (Germany)): Edeltraud Elsner-Lakeberg v Land Nordrhein-Westfalen (Article 141 EC — Directive 75/117/EEC — National measure providing that full-time and part-time teachers are obliged to work the same number of additional hours before being entitled to remuneration — Indirect discrimination against women teachers employed part-time)