@article{oai:repository.dl.itc.u-tokyo.ac.jp:00040103, author = {Nakayama, Noboru}, issue = {3}, journal = {Journal of mathematical sciences, the University of Tokyo}, month = {Oct}, note = {application/pdf}, pages = {293--498}, title = {Classification of log del~Pezzo surfaces of index two}, volume = {14}, year = {2007} }