The link below is to an article that looks at the popes and includes a full list of each and every pope.
For more visit:
http://www.guardian.co.uk/news/datablog/2013/feb/13/popes-full-list
The link below is to an article concerning Pope Benedict XVI.
For more visit:
http://thegospelcoalition.org/blogs/tgc/2013/02/11/9-things-you-should-know-about-pope-benedict-xvi/
The link below is to an article that looks at four other popes who resigned in the past.
For more visit:
http://mentalfloss.com/article/48865/4-other-popes-who-resigned