13 SEC. 15. Conservation of Cultural Property. - All intervention works and measures on conservation of national cultural treasures, important cultural property, as well as national historical landmarks, sItes or monuments and structures previously marked by the National Museum andlor the National Historical Institute before the Implementation of this Act, shall be undertaken through the appropriate cultural agency which shall supervise the same. The appropriate cultural agency shall approve only those methods and materials that strictly adhere to the accepted international standards of conservation. SEC. 16. Documentation and Preservation of Traditional and Contemporary Arts. - Local government units shall document traditional and contemporary arts and crafts, including their processes and makers, and sustain the sources of their raw materials. Local government units shall epcourage and sustain traditional arts and crafts as active and vtable sources of income for the community. The Commission, the Department of Trade and Industry, the Department of Tourism and other government agencies involved directly or indirectly in the production of goods shall assist the local government units in protecting their traditional and contemporary arts and crafts, making them viable for current and future markets, with a view to encouraging and promoting the unique herItage and identities of said communities. The local government umt concerned shall submit an annual inventory of these documentations to the Commission, which will be included in the Philippine Registry of Cultural Property, as established in Section 14 of this Act. SEC. 17. Systematic Research in Natural History. The National Museum shall have the authority to collect, maintain and develop the national reference collections of Philippine flora and fauna, rocks and minerals through research and field collection of specimens including important cultural property within the territorial jurisdiction of the Philippines. It shall be exempt from any and all permit systems regulating the same.