Papal Encyclicals 

  Vatican Homepage - You should be able to find any document you need here.  

Papal Encyclicals Online  - an extensive list of Papal Encyclicals including some Popes back to the 12th century. 

RCnet - List of Papal Encyclicals. Many are from the 1800's and some from before then.    

St.Gabriel's Bookstore   If you need to buy the print version look here.