1. THE EXCENTER OF A TRIANGLE IN LOBACHEVSKY GEOMETRY Delta " Five Minds " Vector Representation 罗氏三角形的傍心三角形五心的向量表示
2. THE EXCENTER OF A TRIANGLE IN LOBACHEVSKY GEOMETRY Delta " Five Minds " Vector Representation 罗氏三角形的傍心三角形五心的向量表示