1. O’Connor P. Multiple Sclerosis. The facts you need. Fifth edition. 2014. ISBN 978-1-926803-09-8. https://mssociety.ca/library/document/p5eBLiuqo1S4M9Fnz2TYbKQgfmv0ajRC/original.pdf
2. National Multiple Sclerosis Society. What is MS? https://www.nationalmssociety.org/NationalMSSociety/media/MSNationalFiles/Brochures/Brochure-What-Is-MS.pdf