Since 1923, all courses given at the Academy are, in principle, published in the language in which they were delivered in the Collected Courses of the Hague Academy of International Law (in French : Recueil des cours de l'Académie de droit international de La Haye). All the volumes of the Collected Courses which have been published since 1923 are available, since the very first volume (green binder), also in electronic format and paperback books for some courses. The series The Hague Academy of International Law Monographs, proposes revised and updated versions of certain courses given during the Summer programme. The scientific works of the Centre, have been published, since the Centre's 1985 session, in a publication in which the Directors of Studies report on the state of research of the Centre under their direction. When the work of the Centre has been of particular interest and originality, the reports of the Directors of Studies together with the articles by the researchers form the subject of a collection published in the series The Law Books of the Academy. The Academy organizes Colloquia which works are published in the Law Books of the Academy series.