9 ETS 166 – European Convention on Nationality, 6.XI.1997 a Article 21, paragraph 3, sub-paragraph c, of this Convention shall apply to persons who have been exempted from their military obligations or have fulfilled civil service as an alternative; b persons who are nationals of a State Party which does not require obligatory military service shall be considered as having satisfied their military obligations when they have their habitual residence in the territory of that State Party. Nevertheless, they should be deemed not to have satisfied their military obligations in relation to a State Party or States Parties of which they are equally nationals and where military service is required unless the said habitual residence has been maintained up to a certain age, which each State Party concerned shall notify at the time of signature or when depositing its instruments of ratification, acceptance or accession; c also persons who are nationals of a State Party which does not require obligatory military service shall be considered as having satisfied their military obligations when they have enlisted voluntarily in the military forces of that Party for a total and effective period which is at least equal to that of the active military service of the State Party or States Parties of which they are also nationals without regard to where they have their habitual residence. Chapter VIII – Co-operation between the States Parties Article 23 – Co-operation between the States Parties 1 2 With a view to facilitating co-operation between the States Parties, their competent authorities shall: a provide the Secretary General of the Council of Europe with information about their internal law relating to nationality, including instances of statelessness and multiple nationality, and about developments concerning the application of the Convention; b provide each other upon request with information about their internal law relating to nationality and about developments concerning the application of the Convention. States Parties shall co-operate amongst themselves and with other member States of the Council of Europe within the framework of the appropriate intergovernmental body of the Council of Europe in order to deal with all relevant problems and to promote the progressive development of legal principles and practice concerning nationality and related matters. Article 24 – Exchange of information Each State Party may at any time declare that it shall inform any other State Party, having made the same declaration, of the voluntary acquisition of its nationality by nationals of the other State Party, subject to applicable laws concerning data protection. Such a declaration may indicate the conditions under which the State Party will give such information. The declaration may be withdrawn at any time.