"-Squad Jam-" should be removed from the thread title. While the series so far is about the Squad Jam tournament, both the second and third book changed that part to "2nd Squad Jam",
The namnig scheme is roman numerals after "Gun Gale Online" (I, II, III, IV), followed by a subtitle ("Squad Jam", or "2nd Squad Jam" in this case)
See the english titles on the covers: