mededelingen en verhandelingen. serie b On the formation of drops in clouds and fog / R.R. Vierhout report / nationaal luchtvaartlaboratorium amsterdam Reliability of the drop weight reduction method for simulating wing lift effect in landing gear drop tests / W.K.G. Floor Drop your foreign accent : Engelse uitspraakoefeningen / G. Nolst Trenité Roomsch-katholiek solidarisme in theorie en practijk / W. Drop
