- http://dictionary.all-channel.com
- http://profiles.tigweb.org/EM0
- http://www.123helpme.com
- http://www.bbc.co.uk/worldservice/learningenglish/general/talkaboutenglish/2009/04/090427_tae_al.shtml
- http://www.breakingnewsenglish.com
- http://www.dartmouth.edu/~acskills/success/index.html
- http://www.englishgrammarsecrets.com/