Vitamin D supplementation - Grassroots
http://www.grassrootshealth.net

A great summary chart
other charts are attached at the bottom of this page
See also VitaminDWiki
How often might 50,000 IU vitamin D be taken - results of clinical trials
Search VitaminDWiki for Grassroots or Grassrootshealth 818 items as of Jan 2013
Response to Vitamin D: summary chart of 8 studies – March 2013
Grassroots Health participants Vitamin D vs age, intake, and resulting level – Sept 2013