Nonverbal Communication across Disciplines: Volume 2: Paralanguage, kinesics, silence, personal and environmental interaction. John Benjamins Publishing. p. 162. ISBN 9789027297112. ↑ Robert Eklund (2008): Pulmonic ingressive phonation: Diachronic and synchronic characteristics, distribution and function in animal and human sound production and in human speech, Journal of the International Phonetic Association, vol.