certain basic issues. 24. She considered that the study should be prepared within the framework of the problems involving persons belonging to national, ethnic, religious and linguistic minorities. She suggested that the study should not deal with problems facing other minorities, which she would call "social minorities", and which would include migrant workers, aliens, refugees and non-citizens, however much sympathy and concern might be felt for those vulnerable groups. Moreover, certain problems facing the social minorities were already being dealt with in studies by bodies and organs of the United Nations system and by some of the Sub-Commission's Special Rapporteurs. 25. Article 27 of the International Covenant on Civil and Political Rights provided specific legal obligations for the States which had ratified the Covenant. The meaning of the terms "group" and "in community with others" must be analysed, since it was essential for the purposes of the study to have a unified and clear interpretation of the terms and concepts contained in E/CN.4/Sub.2/1990/SR.l0 page 6 article 27. It was also important to continue to respect the distinction between minorities and indigenous people. The study should also take into account the relevant decisions by the Human Rights Committee. 26. The question of the post-Versailles treaties and other international instruments for the protection of minorities, raised in paragraph 28 of the report, was of paramount legal and practical importance. She noted in that paragraph that the Secretary-General, in his Study on the Legal Validity of the Undertakings Concerning Minorities (E/CN.4/367 and Add.l), on the basis of the principle of changed circumstances (clausula rebus sic stantibus), held that the system of pre-war minority protection had ceased to exist, whereas Mr. Turk, in a recent paper, "Minority Protection in Human Rights Conventions", argued that some of the provisions might still have legal effect. 
**Analysis**
The text appears to be discussing a study on the protection of national, ethnic, religious and linguistic minorities, and the legal obligations of States in this regard. The text references international instruments, such as the International Covenant on Civil and Political Rights, and the Human Rights Committee's decisions. The focus on minority protection and legal obligations suggests that the category should be related to human rights.

**Category**
Humanitarian aid and relief, Education