Collapsible Nested GridView with Paging using ASP.Net

http://aspsnippets.com/Articles/Collapsible-Nested-GridView-with-Paging-using-ASPNet.aspx
http://www.aspsnippets.com/Articles/Nested-GridView-Example-in-ASPNet-using-C-and-VBNet.aspx
http://www.aspdotnet-suresh.com/2012/05/gridview-with-in-gridview-or-nested.html
http://www.dotnetfox.com/articles/multilevel-nested-gridview-in-Asp-Net-using-C-Sharp-1012.aspx
http://www.codeproject.com/Articles/189997/Gridview-inside-Gridview-in-asp-net-Csharp

Editable Nested GridView (All-in-One)

http://www.codeproject.com/Articles/20047/Editable-Nested-GridView-All-in-One