Second Vatican Council, Decree “Orientalium Ecclesiarum”, 21-XI-1964, AAS 57 (1965) 76-89.
4. Means should be taken therefore in every part of the world for the protection and advancement of all the individual Churches and, to this end, there should be established parishes and a special hierarchy where the spiritual good of the faithful demands it. The hierarchs of the different individual Churches with jurisdiction in one and the same territory should, by taking common counsel in regular meetings, strive to promote unity of action and with common endeavor to sustain common tasks, so as better to further the good of religion and to safeguard more effectively the ordered way of life of the clergy.(3)
(3) Pius XII, Motu proprio Cleri sanctitati, 2 iun. 1957, can. 4.
(4) Pius XII, Motu proprio Cleri sanctitati, 2 iun. 1957, can. 8: sine licentia Sedis Apostolicae, sequendo praxim saeculorum praecedentium; item quoad baptizatos acatholicos in can. 11 habetur: ritum quem maluerint am plecti possunt; in textu proposito disponitur modo positivo observantia ritus pro omnibus et ubique terrarum.