Andreas Brandstädt Victor Chepoi Feodor F. Dragan Distance Approximating Trees for Chordal and Dually Chordal Graphs (Extended Abstract). 78-91 1997 conf/esa/1997 ESA db/conf/esa/esa97.html#BrandstadtCD97 http://dx.doi.org/10.1007/3-540-63397-9_7