Tham khảo Đường_tròn_nội_tiếp_và_bàng_tiếp

  • Altshiller-Court, Nathan (1925), College Geometry: An Introduction to the Modern Geometry of the Triangle and the Circle (ấn bản 2), New York: Barnes & Noble, LCCN 52013504
  • Kay, David C. (1969), College Geometry, New York: Holt, Rinehart and Winston, LCCN 69012075
  • Kimberling, Clark (1998). “Triangle Centers and Central Triangles”. Congressus Numerantium (129): i–xxv, 1–295.
  • Kiss, Sándor (2006). “The Orthic-of-Intouch and Intouch-of-Orthic Triangles”. Forum Geometricorum (6): 171–177.