IXe [i.e. Neuvième] congrès :
livret-guide de l'excursion.
APA Citation
International Congress of Prehistoric and Protohistoric Sciences. 9th, N., International Union of Prehistoric and Protohistoric Sciences. (1976). IXe [i.e. Neuvième] congrès: livret-guide de l'excursion. [Paris?]: [International Union of Prehistoric and Protohistoric Sciences?].
MLA Citation
International Congress of Prehistoric and Protohistoric Sciences. 9th, Nice, 1976, and International Union of Prehistoric and Protohistoric Sciences. IXe [i.e. Neuvième] Congrès: Livret-guide De L'excursion. [Paris?]: [International Union of Prehistoric and Protohistoric Sciences?], 1976.
Warning: These citations may not always be complete (especially for serials).