Source: http://ewtn.com/library/curia/cedinsumpon.HTM
Timestamp: 2019-04-19 19:08:38+00:00

Document:
15. A coetus fidelium ("group of the faithful") can be said to be stabiliter existens ("existing in a stable manner"), according to the sense of art. 5 § 1 of the Motu Proprio Summorum Pontificum, when it is constituted by some people of an individual parish who, even after the publication of the Motu Proprio, come together by reason of their veneration for the Liturgy in the Usus Antiquior, and who ask that it might be celebrated in the parish church or in an oratory or chapel; such a coetus ("group") can also be composed of persons coming from different parishes or dioceses, who gather together in a specific parish church or in an oratory or chapel for this purpose.
a.) Every Catholic priest who is not impeded by Canon Law7 is to be considered idoneus ("qualified") for the celebration of the Holy Mass in the forma extraordinaria.
30. As regards tonsure, minor orders and the subdiaconate, the Motu Proprio Summorum Pontificum does not introduce any change in the discipline of the Code of Canon Law of 1983; consequently, in Institutes of Consecrated Life and Societies of Apostolic Life which are under the Pontifical Commission Ecclesia Dei, one who has made solemn profession or who has been definitively incorporated into a clerical institute of apostolic life, becomes incardinated as a cleric in the institute or society upon ordination to the diaconate, in accordance with canon 266 § 2 of the Code of Canon Law.
33. If there is a qualified priest, a coetus fidelium ("group of faithful"), which follows the older liturgical tradition, can also celebrate the Sacred Triduum in the forma extraordinaria. When there is no church or oratory designated exclusively for such celebrations, the parish priest or Ordinary, in agreement with the qualified priest, should find some arrangement favourable to the good of souls, not excluding the possibility of a repetition of the celebration of the Sacred Triduum in the same church.
3 Cf. Code of Canon Law, Canon 838 §1 and §2.
4 Cf. Code of Canon Law, Canon 331.
5 Cf. Code of Canon Law, Canons 223 § 2 or 838 §1 and §4.
6 BENEDICTUS XVI, Epistola ad Episcopos ad producendas Litteras Apostolicas motu proprio datas, de Usu Liturgiae Romanae Instaurationi anni 1970 praecedentis, AAS 99 (2007) 799.
7 Cf. Code of Canon Law, Canon 900 § 2.
8 Cf. Code of Canon Law, Canon 249; Second Vatican Ecumenical Council, Constitution Sacrosanctum Concilium, 36; Declaration Optatum totius, 13.9 BENEDICTUS XVI, Epistola ad Episcopos ad producendas Litteras Apostolicas motu proprio datas, de Usu Liturgiae Romanae Instaurationi anni 1970 praecedentis, AAS 99 (2007) 797.

References: art. 5
 § 1
 § 2
 §1
 §2
 § 2
 §1
 §4
 § 2