Disorders of the Nervous System Caused by Drugs, Toxins, and Chemical Agents, Diptheria
Adams & Victors Principles of Neurology Chp 43, pg 1217, Ropper, A.H.,et al, 2014
Internal Ophthalmoplegia, In Ocular Differential Diagnosis
Lea & Febiger, Phila. p 3375., Roy,F.H., 1975