Talk about the other series being made and were they can be found.
Well I have looked around and found about nothing for blue shift and opposing force (source).
This is all I have found for Blue Shift.
https://s13.invisionfree.com/Blue_Shift_Source/
All topics I have found for Opposing force in source talk about all the Modders coming to a dead end. lack of interest I believe.
Like Opposing source I believe is dead.