More than one tough chordal planar graphs are Hamiltonian
Thomas J. Böhme, Jochen Harant, Michal Tkáč · Journal of Graph Theory · 1999
We prove the result stated in the title. Furthermore, it is proved that for any ϵ > 0, there is a 1-tough chordal planar graph Gϵ such that the length of a longest cycle of Gϵ is less than ϵ|V(Gϵ)|. © 1999 John Wiley & Sons, Inc. J. Graph Theory 32: 405–410, 1999