Hawkins CF, Swisher WE (1978) Evaluation of real-time ultrasound scanner in assessing lateral pharyngeal wave motion during speech. Cleft Palate J 15:161
King EW (1952) A roentgenographic study of pharyngeal growth. Angle Orthod 22:23
McWilliams BJ, Morris HS, Shelton RL (eds) (1984) Instruments for assessing velopharyngeal mechanisms in cleft palate speech. CV Mosby, St. Louis
Prusansky S (1953) Description, classification, and analysis of unoperated clefts of the lip and palate. Am J Orthod 39:590CrossRef
Ricketts RM (1954) The cranial base and soft structures in cleft palate speech and breathing. Plast Reconstr Surg 14:74
Rosenberger HC (1934) Growth and development of the nasorespiratory area in childhood. Ann Otol Rhinol Laryngol 43:495