by (United States)B.Bollobas;by (Federal Republic of Germany)B.Bollobas; by (United States)B.Booss;by (Federal Republic of Germany)A.Csaszar; by (United States)B.Gellbaum;by (Federal Republic of Germany)Z.Nitecki; by (United States)A.E.Wier;by (Federal Republic of Germany)B.Bartok; by (United States)D.Margaret;by (Federal Republic of Germany)H.Boll; by (United States)F.H.Croon;by (Federal Republic of Germany)A.Dold; by (United States)B.E.Conway;by (Federal Republic of Germany)D.Britz; by (United States)N.Ikeda;by (Federal Republic of Germany)B.Okdendal; by (United States)T.S.Moss;by (Federal Republic of Germany)B.R.Nag; by (United States)G.Lindblad;by (Federal Republic of Germany)L.Beltzmann;