Ladefoged, Peter; & Maddieson, Ian. (1996). The sounds of the world's languages. Oxford: Blackwell Publishers. ISBN 0-631-19814-8 (hbk); ISBN 0-631-19815-6 (pbk).
Ladefoged, Peter; & Wu, Zhongji. (1984). Places of articulation: An investigation of Pekingese fricatives and affricates. Journal of Phonetics, 12, 267-278.
