3 Wherefore the sacred Council judges that the following principles concerning the promotion and reform of the liturgy should be called to mind, and that practical norms should be established. Among these principles and norms there are some which can and should be applied both to the Roman rite and also to all the other rites. The practical norms which follow, however, should be taken as applying only to the Roman rite, except for those which, in the very nature of things, affect other rites as well.
Source: Sacrosanctum Concilium (Vatican.va)