"Ryoso Hamane,Toshiya Itoh,Kouhei Tomita","Approximation Algorithms for the Highway Problem under the Coupon Model",,"IEICE Trans. on Fundamentals","IEICE","Vol. E92-A","No. 8","pp. 1779-1786",2009,Aug.
"Ryoso Hamane,Toshiya Itoh,Kouhei Tomita","Approximation Preserving Reductions among Item Pricing Problems",,"IEIC Transactions on Information and Systems","IEICE","Vol. E92.D","No. 2","pp. 149-157",2009,Feb.
"Toshiya Itoh,Ryoso Hamane","Improved Approximation Allgorithms for Item Pricing with Bounded Degree and Valuation",,"IEICE Trans. on Information and Systems",,"Vol. 91-D","No. 2","pp. 187-199",2008,Feb.
"Ryoso Hamane,Toshiya Itoh,Kouhei Tomita","Approximation Algorithms for the Highway Problem under the Coupon Model",,"arXiv",,,"No. 0712.2629v1",,2007,Dec.