International Labor Office, Berthelot, M, International Labor Office, International Labor Office, International Labor Office, International Labor Office, . . . Lazard, M. (1975). Coal production in the Ruhr district (end of May 1920): Enquiry by the International Labour Office. Nendehln, Kraus Reprint.
Citazione stile Chigago Style (17a edizione)International Labor Office, et al. Coal Production in the Ruhr District (end of May 1920): Enquiry by the International Labour Office. [Geneva]: Nendehln, Kraus Reprint, 1975.
Citatione MLA (9a ed.)International Labor Office, et al. Coal Production in the Ruhr District (end of May 1920): Enquiry by the International Labour Office. Nendehln, Kraus Reprint, 1975.
Attenzione: Queste citazioni potrebbero non essere precise al 100%.