European social charter = Charte sociale européenne.

MLA

European Social Charter = Charte Sociale Européenne. 3rd ed. [Strasbourg]: [Council of Europe], 1966.

APA

(1966). European social charter = Charte sociale européenne. 3rd ed. [Strasbourg]: [Council of Europe].

Chicago

European Social Charter = Charte Sociale Européenne. 3rd ed. [Strasbourg]: [Council of Europe], 1966.