1. Alon, N., Mubayi, D., Thomas, R.: Large induced forests in sparse graphs. J. Graph Theory 113, 113–123 (2001) MR 1859785
2. Borradaile, G., Eppstein, D., Zhu, P.: Planar induced subgraphs of sparse graphs (2014), arXiv:1408.5939
3. Borradaile, G., Klein, P., Marx, D., Mathieu, C.: Algorithms for Optimization Problems in Planar Graphs (Dagstuhl Seminar 13421). Dagstuhl Reports 3(10), 36–57 (2014)
4. Călinescu, G., Fernandes, C.G., Finkler, U., Karloff, H.: A better approximation algorithm for finding planar subgraphs. J. Algorithms 27(2), 269–302 (1998) MR 1622397
5. Lecture Notes in Computer Science;C. Cheng,2011