Llobera Vila, Mireia. “Legislator and Collective Bargaining ‘substitution Effect’ in the Application of the Principle of Proportionality by the ECJ”. Lex Social: Journal of Social Rights, vol. 6, no. 2, July 2016, pp. 48-68, https://upo.es/revistas/index.php/lex_social/article/view/1974.