四角形((Convex) Quadrilateral)
内接円を持つ四角形(Tangential Quadrilateral)
http://gogeometry.blogspot.com/2008/08/elearn-geometry-problem-153.html
Heinrich Dorrie, D. Antin, "One Hundred Great Problems of Elementary Mathematics: Their History and Solution (Dover classics of science & mathematics)", Dover Publications; Softcover Ed edition (June 1, 1965)
Heinrich Dorrie, D. Antin, "One Hundred Great Problems of Elementary Mathematics: Their History and Solution (Dover classics of science & mathematics)", Dover Publications; Softcover Ed edition (June 1, 1965)
http://www.amazon.com/Problems-Elementary-Mathematics-classics-mathematics/dp/0486613488 ( http://books.google.com/books?id=i4SJwNrYuAUC&dq の英訳)
清宮俊雄, 『幾何学 改訂版 (モノグラフ 26)』,科学新興社
特殊な変な物
山司勝紀, 西田知己, 『和算の事典』, 朝倉書店