situations of trafficking in persons, which necessarily entailed violations of rights established in the Convention. 77. The representatives pointed to the Court’s consistent criteria that, when examining the compatibility of State laws or conducts with the Convention, it could interpret the obligations and the rights contained in this instrument in light of other treaties. They also indicated that they had alleged specific violations owing to the State’s omission of its obligation to ensure rights in relation to the prohibition of slavery, servitude and trafficking (Article 6 of the Convention), in relation to the rights to juridical personality, personal integrity, personal liberty, privacy, honor and dignity, freedom of movement and residence of the victims who were in Hacienda Brasil Verde after December 1998. F.2. Considerations of the Court 78. It is important to note that, in this case, neither the Commission nor the representatives have asked the Court to declare the State responsible for possible violations of international commitments assumed by Brazil in relation to other international treaties. 79. Pursuant to Article 29(b) of the American Convention and the general rules for the interpretation of treaties included in the Vienna Convention on the Law of Treaties, the American Convention may be interpreted in relation to other international instruments.50 Therefore, when examining the compatibility with the Convention of a State’s laws or actions, the Court may interpret the obligations and the rights contained in that instrument in light of other treaties. This means that the Court may observe the rules of specific international norms relating to the prohibition of slavery, servitude and trafficking in persons, in order to apply the norms of the Convention more precisely when defining the scope of the State’s obligations.51 Therefore, the State’s allegation of lack of jurisdiction is groundless, because the interpretation of the scope of Article 6 of the Convention is not a matter for a preliminary objection, but corresponds to the examination of the merits of the case. 80. Based on the above, the Court rejects this preliminary objection. G. Alleged lack of jurisdiction ratione materiae concerning supposed violations of labor rights G.1. Arguments of the State and observations of the Commission and of the representatives 81. The State alleged that: (i) the Additional Protocol to the American Convention in the Area of Economic, Social and Cultural Rights (Protocol of San Salvador) indicated clearly that only trade union rights and the right to education were subject to the system of individual petitions regulated by the Convention, and (ii) the facts verified in Hacienda Brasil Verde related to situations of violation of the right to fair, equitable and satisfactory working conditions, which were regulated in Article 7 of the Protocol of San Salvador, and not in Article 6 of the American Convention. Accordingly, the State indicated that, since the facts of Cf. Case of the Mayagna (Sumo) Awas Tingni Community v. Nicaragua. Merits, reparations and costs. Judgment of August 31, 2001. Series C No. 79, para. 148, and Case of Rodríguez Vera et al. (Disappeared from the Palace of Justice) v. Colombia. Preliminary objections, merits, reparations and costs. Judgment of November 14, 2014. Series C No. 287, para. 39. In this regard, Article 31.3.c of the said Vienna Convention establishes as a rule of interpretation that: “[t]here shall be taken into account, together with the context: […] c) any relevant rules of international law applicable in the relations between the parties.” 50 Cf. Case of the Santo Domingo Massacre v. Colombia. Preliminary objections, merits and reparations. Judgment of November 30, 2012. Series C No. 259, para. 24, and Case of Rodríguez Vera et al. (Disappeared from the Palace of Justice), para. 39. 51 21