Neisseriae 1990: Proceedings of the Seventh International Pathogenic Neisseriae Conference, Berlin, Federal Republic of Germany, September 9–14, 1990. :321-326
Neisseriae 1990: Proceedings of the Seventh International Pathogenic Neisseriae Conference, Berlin, Federal Republic of Germany, September 9–14, 1990. :295-300
Neisseriae 1990: Proceedings of the Seventh International Pathogenic Neisseriae Conference, Berlin, Federal Republic of Germany, September 9–14, 1990. :301-306