The double undercut is what you are describing. It was popularized by Dai Vernon but it was not created by him. For a move as simple as a break you are going to have a hard time finding a source. Same for what is essentially cutting at the break.
The oldest systematic teaching in card technique is in erdnase.
But, i think eather, that he only wrote it and didnt invent it.
Erdnase is a classic, and a trend setter. It did a lot, but it really wasn't the first "systematic teaching in card technique". Then again, perhaps your definition of systematic differs from my own.
Almost all of Professor Hoffman's books predate Erdnase. August Roterberg published several books on card magic before Erdnase.
Erdnase outlines the motion of creating an injog while pushing in a card in his description of the diagonal palm shift. I don't know if he was the first to do so. Hoffman explains the pass in his books and I'm sure Maskelynne uses the break in Sharps and Flats. I'd have to reread my copies to be sure.