The co-operative societies of producers and of consumers and associations thereof shall be incorporated, at their request and after consideration of their form of organization and peculiarities, into the system of collectivism. ARTICLE 157 Labour is under the special protection of the Commonwealth. The Commonwealth will adopt a uniform labour law. ARTICLE 158 Intellectual labour, the rights of the author, the inventor and the artist enjoy the protection and care of the Commonwealth. The products of German scholarship, art, and technical science shall also be recognized and protected abroad through international agreement. ARTICLE 159 The right of combination for the protection and promotion of labour and economic conditions is guaranteed to everybody and to all professions. All agreements and measures which attempt to limit or restrain this liberty are unlawful. ARTICLE 160 Any one employed on a salary or as a wage-earner has the right to the leave necessary for the exercise of his civil rights and, so far as the business is not substantially injured thereby, for performing the duties of public honorary offices conferred upon him. To what extent his right to compensation shall continue will be determined by law. ARTICLE 161 For the purpose of conserving health and the ability to work, of protecting motherhood, and of guarding against the economic effects of age, invalidity and the vicissitudes of life, the Commonwealth will adopt a comprehensive system of insurance, in the management of which the insured shall predominate. ARTICLE 162 The Commonwealth commits itself to an international regulation of the legal status of the workers, which shall strive for a standard minimum of social rights for the whole working class of the world. ARTICLE 163 Every German has, without prejudice to his personal liberty, the moral duty so to use his intellectual and physical powers as is demanded by the welfare of the community. Every German shall have the opportunity to earn his living by economic labour. So long as suitable employment can not be procured for him, his maintenance will be provided for. Details will be regulated by special national laws. ARTICLE 164 The independent agricultural, industrial, and commercial middle class shall be fostered by legislation and administration, and shall be protected against oppression and exploitation. ARTICLE 165 Wage-earners and salaried employés are qualified to co-operate on equal terms with the employers in the regulation of wages and working conditions, as well as in the entire economic development of the productive forces. The organizations on both sides and the agreements between them will be recognized.