Art. 2971. Pleading and service of process Except as otherwise provided by law, the rules of pleading and service of process applicable in ordinary proceedings shall apply to succession proceedings. A certified copy of the petition, opposition, contradictory motion, or rule initiating a contradictory succession proceeding shall be served on the adverse party; but citation is necessary only in those cases in which it is specifically required by law. An opposition may be served upon the adverse party as provided in Article 1313.