Available from: https://www.ncbi.nlm.nih.gov/books/NBK1826/ ↑ van Lier, Margot G. F.; Westerman, Anne Marie; Wagner, Anja; Looman, Caspar W. N.; Wilson, J. H. Paul; de Rooij, Felix W. M.; Lemmens, Valery E. P. P.; Kuipers, Ernst J.; Mathus-Vliegen, Elisabeth M. H. (2011-02-01).