Trillingsmeetapparaten / Philips' gloeilampenfabrieken, afd. industriele meet- en regelapparaten publicaties study of bessel functions in connection with the problem of two mutually attracting circular discs / by C.J. Bouwkamp publicaties Concerning a new transcendent, its tabulation and application in antenna theory / by C.J. Bouwkamp publicaties Distorsie van signalen met frequentiemodulatie bij doorgang door electrische netwerken / door F.L.H.M. Stumpers Publicaties / Laboratoria, N.V. Philips' Gloeilampenfabrieken