Cita APA (7a ed.)

Koops, W. R. H., Koops, W. R. H., & Wieder, J. (1977). IFLA's First Fifty Years: Achievement and challenge in international librarianship (Reprint 2011.). De Gruyter.

Cita Chicago Style (17a ed.)

Koops, Willem Roelf Henderikus, Willem Roelf Henderikus Koops, y Joachim Wieder. IFLA's First Fifty Years: Achievement and Challenge in International Librarianship. Reprint 2011. Berlin ; Boston: De Gruyter, 1977.

Cita MLA (9a ed.)

Koops, Willem Roelf Henderikus, et al. IFLA's First Fifty Years: Achievement and Challenge in International Librarianship. Reprint 2011. De Gruyter, 1977.