Aug 01, 2019 11:37 PM|KathyW|LINK
ScriptReference with just a Name has to have that name defined elsewhere (and the name could be just bootstrap, if you wanted it to be).
See for example:
https://devblogs.microsoft.com/aspnet/asp-net-4-5-scriptmanager-improvements-in-webforms/ You'll see the examples show how MsAjaxBundle and jquery are defined.
If bootstrap is not similarly defined, follow those examples.