blocking sites

I had to go and block Wow! eBooks and ShareBookFree. I spent too much time on the sites looking for books. Even though most of the searches were for IT manuals, I did not need to spend that much time there. Not right now. Searching for a manual or two can be done in the 10 minutes that I have alloted myself. I don't need to look for the books uploaded for the last month before 4pm.