Journal article (2004) - J Friml (author), X Yang (author), PJJ Hooykaas (author), K Palme (author), R Offringa (author), M Michniewicz (author), D Weijers (author), A Quint (author), O Tietz (author), R Benjamins (author), PBF Ouwerkerk (author), K Ljung (author), G Sandberg (author)