[音韻] Acoustic-perceptual method(Beddor, Brasher, and Narayan...)

Narayan's curriculum vita http://www.sas.upenn.edu/~cnarayan/CV_cn.pdf

Articulatory characteristics of Hungarian ‘transparent’ vowels
Stefan Benusa, , 1, , and Adamantios I. Gafosa, b, http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6WKT-4NN1TC1-1&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=8a450928f61c8261d489dae2786b1daf

Michigan linguistics
http://ling.lsa.umich.edu/doc/home/newsletter06.pdf