You dont use a , when you punctuate USD you use a .
Well that settles it then. 
You dont use a , when you punctuate USD you use a .
Well that settles it then.
Founded in 2004, Leakfree.org became one of the first online communities dedicated to Valve’s Source engine development. It is more famously known for the formation of Black Mesa: Source under the 'Leakfree Modification Team' handle in September 2004.