Books:  
o R.H. van Gulik: “The lore of the Chinese lute"
More Information + Order: Here
o Alan R. Thrasher: “Chinese Musical Instruments” (Images of Asia)
More Information + Order: Here
o Laurence E. R. Picken (Editor): ”Music from the Tang Court: Volume 6”
More Information + Order: Here
o Bell Yung:“Cantonese Opera : Performance as Creative Process”(Cambridge Studies in Ethnomusicology)
More Information + Order: Here
o A. C Moule: “A list of the musical and other sound-producing instruments of the Chinese”
More Information + Order: Here
o John Myers: “The Way of the Pipa: Structure and Imagery in Chinese Lute Music” (World Musics)
More Information + Order: Here
o Joseph S. C. Lam: “State Sacrifices and Music in Ming China: Orthodoxy, Creativity, and Expressiveness”
More Information + Order: Here
o Lothar Von Falkenhausen: “Suspended Music: Chime Bells in the Culture of Bronze Age China”
More Information + Order: Here
o Stephen Jones: “Folk Music of China: Living Instrumental Traditions” (Clarendon Paperbacks)
More Information + Order: Here
o Rachel Harris: “Singing The Village: Music, Memory And Ritual Among The Sibe Of Xinjiang” 
More Information + Order: Here
o Jenny F. So: “Music in the Age of Confucius”
More Information + Order: Here
o J. Lawrence Witzleben: “Silk and Bamboo-Music in Shanghai: The Jiangnan Sizhu Instrumental Ensemble Tradition”
More Information + Order: Here
o Xiao Mei, Bell Yung, Anita Wong: “The Musical Arts of Ancient China”
More Information + Order: Here
o Sin-Yan Shen: “Chinese Music and Orchestration: A Primer on Principles and Practice”
More Information + Order: Here
o Helen Rees: “Echoes of History: Naxi Music in Modern China”
More Information + Order: Here
o Mingyue Liang: “Music of the Billion: An Introduction to Chinese Musical Culture”
More Information + Order: Here
o James Binkley: “Abiding with antiquity - the Qin zither”
More Information + Order: Here

CDs:
The number of audio CDs dealing with “traditional” music is huge, this is why I only like to recommend CDs that I know.
If you like to get an overview of CDs on the market, you can check an Amazon-research here.

o Luis Chen:  “Plays Zheng“ (Instrumental tracks)
More Information + Order: Here
o Liu Fang:   “Chinese traditional Pipa music“ (Instrumental tracks)
More Information + Order: Here
o Chen Gongliang:   “Sound of autumn" (Double CD, Qin)
More Information + Order: Here
o The vibrant rhythm:   Guqin music
More Information + Order: Here
o Musique des Peuples Minoritaires de Taiwan
More Information + Order: Here