sna introduction
  * [[:social network analysis]]
    * [[:social network analysis#eg3 concor| eg 3]]
      * [[:hawthorne studies]]  
    * [[:social network analysis#draft| eg in history study]]
    * in r [[:r:social network analysis tutorial]]
    * [[:text mining]] eg
references 
  * https://kuduz.tistory.com/1087