Reducing Hajós' 4-coloring conjecture to 4-connected graphs. - Xingxing Yu; Florian Zickfeld (J. Comb. Theory B, 2006)

On the Number of alpha -Orientations. - Stefan Felsner; Florian Zickfeld (WG, 2007)

Spanning Trees with Many Leaves in Graphs without Diamonds and Blossoms. - Paul S. Bonsma; Florian Zickfeld (LATIN, 2008)

On the Number of Planar Orientations with Prescribed Degrees. - Stefan Felsner; Florian Zickfeld (Electron. J. Comb., 2008)

Schnyder Woods and Orthogonal Surfaces. - Stefan Felsner; Florian Zickfeld (Discret. Comput. Geom., 2008)

A 3/2-Approximation Algorithm for Finding Spanning Trees with Many Leaves in Cubic Graphs. - Paul S. Bonsma; Florian Zickfeld (SIAM J. Discret. Math., 2011)

Improved bounds for spanning trees with many leaves. - Paul S. Bonsma; Florian Zickfeld (Discret. Math., 2012)