[1] Isala Klin, Dept Paediat, NL-8000 GM Zwolle, Netherlands
[2] Asthma Ctr Heideheuvel, Hilversum, Netherlands
[3] Maasland Hosp, Sittard, Netherlands
[4] Groene Hart Hosp, Gouda, Netherlands
[5] Med Spectrum Twente, Enschede, Netherlands
[6] Ikazia Hosp, Rotterdam, Netherlands
[7] St Clara Hosp, Rotterdam, Netherlands