Reference:

1) http://www.webmd.com/hypertension-high-blood-pressure/guide/blood-pressure-causes

2) http://www.who.int/mediacentre/factsheets/fs310/en/

3) http://hyper.ahajournals.org/content/46/4/714.full

4) http://link.springer.com/article/10.1007%2FBF00846560#page-1

5) http://stroke.ahajournals.org/content/31/3/568.abstract

6) https://www.nlm.nih.gov/medlineplus/ency/article/007484.htm

7) http://www.ncbi.nlm.nih.gov/pubmed/320955

8) http://www.nature.com/jhh/journal/v15/n4/abs/1001147a.html

9) http://www.nature.com/jhh/journal/v23/n5/full/jhh2008135a.html

10) http://hyper.ahajournals.org/content/26/5/820.long

11)http:// www.ijhsr.org/currentissue_html_2.htm

12) http://www.ncbi.nlm.nih.gov/pubmed/3072179