Early detection of upper airway obstructions by analysis of acoustical respiratory input impedance. - S. Reisch; Holger Steltner; Jens Timmer; Christine Renotte; Josef Guttmann (Biol. Cybern., 1999)

Detection and Classification of Sleep-Disordered Breathing Using Acoustic Respiratory Input Impedance and Nasal Pressure. - Holger Steltner; Richard Staats; Michael Vogel; Christian Virchow; Heinrich Matthys; Josef Guttmann; Jens Timmer (ISMDA, 2000)