<http://www.w3.org/1999/02/22-rdf-syntax-ns#first>
<http://cos.h-cdn.co/assets/cm/14/25/539fae3fe5b6a_-_cos-8-period-0512-mdn.jpg>
<http://www.cosmopolitan.com/health-fitness/advice/g2007/period-horror-stories/>