Quantification of functional abilities in Rett syndrome: a comparison between stages III and IV - Monteiro, Carlos Bandeira de Mello; Savelsbergh, Geert J. P; Smorenburg, Ana R. P; Graciani, Zodja; Torriani-Pasin, Camila; Abreu, Luiz Carlos de; Valenti, Vitor E; Kok, Fernando (Neuropsychiatric Disease and Treatment, 2014)