《水经注·卷二十一》
汝水又往东南流，昆水注入。昆水发源于鲁阳县的唐山，往东南流经昆阳县老城西面。
汝水又东南，昆水注之，水出鲁阳县唐山，东南流，径昆阳县故城西。
The Ru River flows southeast again, where the Kun River flows in. The Kun River originates in Tangshan, Luyang County, and flows southeast through the west side of the old city of Kunyang County.