https://www.colgate.com/en-us/oral-health/basics/brushing-and-flossing/how-to-floss
http://www.webmd.com/oral-health/guide/dental-health-dental-care-products#1
http://www.cnn.com/2016/06/08/health/adults-flossing-teeth/index.html
http://www.checkdent.com/en/videos/there-are-no-bad-teeth-297.html
https://www.youtube.com/watch?v=gWhF0WYG7P4
