Proceedings of the twentieth annual convention : Jakarta 8th - 10th October 1991 Proceeding of the fourteenth annual convention Jakarta 8-10, 1985 Proceeding of the eleventh annual convention, Jakarta, June 8-9, 1982 Proceeding of the eleventh annual convention, Jakarta, June 7-8, 1983 Preceeding of the twelfth annual convention, Jakarta, June 7 - 8 1983 Proceeding of the twelfth annual convention, Jakarta June 7 - 8 1983OPECProceedings of the fourteenth annual convention Jakarta 8-10, 1985Proceedings of the eleventh annual convention, Jakarta, June 8-9 1992Proceedings of the eleventh annual convention, Jakarta, June 8-9 1992