- Family Practice Notebook: Horner's Syndrome - The pathophysiology, causes and signs of horners syndrome.
- Georgetown University School of Medicine - A clinical description of horner syndrome, with what lesions or injury it may occur and a brief definition of klympke dejerine syndrome.
- Handbook of Ocular Disease Management - Horner's Syndrome - An article about the signs, symptoms, pathophysiology, management and clinical pearls.
- NORD: Horner's Syndrome - Offer the synonyms, a general discussion and further resources.