The entire body of legal rules that have bearing on work performed under another's authority, involving overlap between private and public law. Individual labour law covers the relations between employer and employee, including the appropriate special regulations. Collective labour law establishes the norms governing the legal relationships of the employees within an establishment (a) with each other and (b) vis-à-vis their employer (in the form of the works constitution and co-determination ) and, beyond this, the legal relationships of the trade unions and employers' associations with each other and vis-à-vis the state. Labour law falls within the field of concurrent legislative powers of the Federation. Its sources of law also include judge-made law , notably that developed by the labour courts.