Reference works are secondary or even tertiary sources, not the kind of thing you cite as current research, but they are excellent starting places when you are beginning research in a new subject area or exploring a new topic. Below are some selected sources available at EMU Library.
Encyclopedic Dictionary of Applied Linguistics by 
Handbook of Cognitive Linguistics and Second Language Acquisition by 
Longman Dictionary of Language Teaching and Applied Linguistics by 
The Handbook of Second Language Acquisition by 
Writing an Applied Linguistics Thesis or Dissertation by 