John, Peter E.; Mallion, Roger B.; Gutman, Ivan;
An algorithm for counting spanning trees in labeled molecular graphs homeomorphic to cata-condensed systems. - In: Journal of chemical information and modeling - Washington, DC : American Chemical Society, ISSN 1549-960X, Bd. 38 (1998), 2, S. 108-112
Abstract published in Advance ACS Abstracts, December 15, 1997

https://doi.org/10.1021/ci970425d

Hoffmann, Armin; Marx, Bernd;
Mathematical modelling of a first order sigma-delta modulator. - In: Journal of difference equations and applications - London [u.a.] : Taylor & Francis, ISSN 1563-5120, Bd. 4 (1998), 6, S. 533-550

In this paper an exact model for a basic, first order sigma-delta-modulator is derived by means of a difference equation with discontinuous nonlinearity. An explicit solution is given in terms of the greatest integer function under certain boundedness and initial conditions of the input signal. Assumptions are made under which the explicit formula remains a solution of the difference equation although the suppositions of the main theorem are violated.

http://dx.doi.org/10.1080/10236199808808161

Kratochvíl, Jan; Tuza, Zsolt; Voigt, Margit;
Complexity of choosing subsets from color sets. - In: Discrete mathematics - Amsterdam [u.a.] : Elsevier, Bd. 191 (1998), 1/3, S. 139-148

http://dx.doi.org/10.1016/S0012-365X(98)00101-0

Fabrici, Igor; Jendrol', Stanislav;
Subgraphs with restricted degrees of their vertices in planar graphs. - In: Discrete mathematics - Amsterdam [u.a.] : Elsevier, Bd. 191 (1998), 1/3, S. 83-90

http://dx.doi.org/10.1016/S0012-365X(98)00095-8

Kratochvíl, Jan; Tuza, Zsolt; Voigt, Margit
Brooks-type theorems for choosability with separation. - In: Journal of graph theory - New York, NY [u.a.] : Wiley, ISSN 1097-0118, Bd. 27 (1998), 1, S. 43-49

http://dx.doi.org/10.1002/(SICI)1097-0118(199801)27:1<43::AID-JGT7>3.0.CO;2-G