On the schools of thought definition, I have used this one: a group  
of scholars who hark back to a single writer or small number of writers for  
inspiration and/or doctrinal support.   Hence the modern Austrian school (in the  
US) harks back to Carl Menger.    There are other Austrian schools (in  
Germany for example) that hark back to Boehm-Bawerk.  The classical school (so named by
Marx) but typically hark back to Adam Smith, etc.  Marxists hark back to  what's his name.
 
I hope this helps. 
 
Laurence S. Moss