Judgment of the Court of 20 November 2001 in Case C-268/99 (reference for a preliminary ruling from the Arrondissementsrechtbank te 's-Gravenhage): Aldona Malgorzata Jany and Others v Staatssecretaris van Justitie (External relations — Association agreements between the Communities and Poland and between the Communities and the Czech Republic — Freedom of establishment — "Economic activities" — Whether or not they include the activity of prostitution)