THz-BRIDGE Spectral Database
http://www.frascati.enea.it/THz-BRIDGE/

NIST THz Spectral Database
http://webbook.nist.gov/chemistry/thz-ir/

RIKEN THz Spectral Database
http://www.riken.jp/THzdatabase/

THz Links from Rice University
http://www-ece.rice.edu/~daniel/groups.html

Terahertz Technology Forum
http://www.terahertzjapan.com/lang_english/index.html

Terahertz Science & Technology Network
http://www.thznetwork.org/wordpress/

RIKEN Tera-Photonics Laboratory
http://www.riken.go.jp/lab-www/tera/TP_HP/index_en.html

Quantum Semiconductor Electronics Laboratory, University of Tokyo
http://thz.iis.u-tokyo.ac.jp/top-e.html

Teraherts Photonics Laboratory, Osaka University
http://www.ile.osaka-u.ac.jp/research/THP/indexeng.html

Solid State Spectroscopy Group, Kyoto University
http://www.hikari.scphys.kyoto-u.ac.jp/e_home.html

Kawase Laboratory "Tera health", Nagoya University
http://www.nuee.nagoya-u.ac.jp/labs/optlab/kawase/index.html

NICT Terahertz Project
http://act.nict.go.jp/thz/en/main_e.html

Laboratory of Terahertz Bioengineering, Tohoku University http://www.agri.tohoku.ac.jp/thz/jp/index_e.htm

Infrared and Raman Users Group
http://www.irug.org/