http://www.codeproject.com/Articles/165159/Custom-Membership-Providers
https://msdn.microsoft.com/en-us/library/f1kyba5e.aspx
https://msdn.microsoft.com/en-us/library/ms366730.aspx
[How Do I:] Create a Custom Membership Provider?
http://www.asp.net/web-forms/videos/how-do-i/how-do-i-create-a-custom-membership-provider
How to: Sample Membership Provider Implementation
https://msdn.microsoft.com/en-us/library/6tc47t75(v=vs.100).aspx