Spoiler alert, Bardock only existed in Monaito's and Gas's memories and as a voice coming out of Bardock's scouter, never appeared actually in battle.
And during the current arc there's so far no word about him.

And the books always tend to come out in 4 chapters (except for the 1st and 2nd ones), and each time the last chapter is already 3 months old by the time the book comes out.
So don't expect it.