Brehm, Merel-Anne, Suzan Verduijn, Jurgen Bon, Nicoline Bredt, and Frans Nollet. 2017. “Comparison of Two 6-Minute Walk Tests to Assess Walking Capacity in Polio Survivors”. Journal of Rehabilitation Medicine 49 (9):732-37. https://doi.org/10.2340/16501977-2264.