Present Perfect Simple and Present Perfect Continuous

In the link you can find a ppt about Present Perfect Simple and Present Perfect Continuous:

http://www.slideshare.net/anarosaleda/present-perfect-simple-and-present-perfect-continuous-presentation

Here is the links about the topic:
http://www.englishpage.com/verbpage/verbs7.htm
http://www.ego4u.com/en/cram-up/grammar/prepersim-preperpro
http://autoenglish.org/gr.percon.i.htm