Invisible web databases

During EIR class we were introduced to one more  search facilities it was invisible web (databases)  using  TP digital portal . We were asked to compared which search facilities are more effective invisible web(databases), search engines, meta-search or subject directories. 

I think it is more effective to search the invisible web databases  when it come to doing school assignment  because it have more relevant topic .  As for search engines sometime is hard to get the  source that is relevant to the topic .

For my topic i will use  factiva  because i can get the information for the newspaper  and i can know the update on my research topic .

i will used EBSCOhosts databases because it has different kind of course that i can choose. I will you this resource if i want to do  some research or to  find some  extra reference for my course  .