There is no way to write a rule book on hold-em or any other game and cover all the variations of rules.
I've seen hold-em played with antes and no blinds.
I've seen cards burned before the 1st two are dealt.
I've seen hold-em played with raise or fold on each player.
I've seen hold-em played with two flops, two turns, and 2 rivers. A player could use his cards in both boards. He could win one and split the pot or he could scoop.
Yes, I've seen all of the above played in casinos.
In fact we invented "Double Flop" hold-em at the Four Queens's. Had people standing in line to play it. It lasted about a year until the newsness wore off.