Biological Maturation, Body Composition, and Growth of Female Gymnasts and Control Groups of Schoolgirls and Girl Swimmers, Aged 8 to 14 Years: A Cross-Sectional Survey of 1064 Girls - Peltenburg, A L; Erich, W B M; Bernink, M J E; Zonderland, M L; Huisveld, I A (International Journal of Sports Medicine, 1984)