1. 1) Adams RD, Victor M:Principle of Neurology 4th ed. McGrawn-Hill, New York, 1989
2. 2) Shimizu H:Development and introduction of inactivated poliovirus vaccines derived from Sabin strains in Japan. Vaccine 2016;34:1975-1985
3. 3) Hao L, Toyokawa S, Kobayashi Y:Poisson-model analysis of the risk of vaccine-associated paralytic poliomyelitis in Japan between 1971 and 2000. Jap J Infect Dis 2008;61:100-103
4. 4) Halstead LS, Rossi CD:Post-polio syndrome:clinical experience with 132 consecutive outpatients. Birth Defects Orig Artic Ser 1987;23:13-26
5. 5) Gonzalez H, Olsson T, Borg K:Management of postpolio syndrome. Lancet Neurol 2010;9:634-642