http://articles.mercola.com/sites/articles/archive/2015/01/11/vitamin-k1-k2.aspx?e_cid=20150111Z1_SNL_NonBuyer_art_1&utm_source=snl&utm_medium=email&utm_content=art1&utm_campaign=20150111Z1-NonBuyer&et_cid=DM64741&et_rid=801376345

Vitamin K1 and K2—Two Underappreciated Nutrients That Are Crucial for Health