Collective labour agreements are private, negotiative deeds which do not apply erga omnes in the same way as a rule of law. Collective agreements apply to individual relationships between persons:

• who are members of the trade unions that are collective agreement signatories;
• who have expressly adhered to the collective agreements under the employment contract;
• who have implicitly accepted the collective agreement through conduct implying an intent, which can be inferred from the constant and prolonged application of the relevant clauses to individual relationships.