The files below can be distributed as described in the MICROSOFT REACTIVE EXTENSTIONS FOR JAVASCRIPT AND .NET LIBRARIES License.

System.Observable.dll
System.CoreEx.dll
System.Reactive.dll
System.Interactive.dll
System.Threading.dll
System.Linq.Async.dll
System.Reactive.Testing.dll
System.Reactive.ClientProfile.dll
System.Reactive.ExtendedProfile.dll