Starting from this SO protected question I'm trying to understand what the difference between those documents:
As you can see those documents have very different prices and I don't know if the cheaper one is valid or is something like draft or cut copy of the real standard.
Did someone buy the INCITS one?
EDIT
As @Chqrlie pointed out: What is the difference between the ANSI and ISO official documents available for a free and the final draft freely accessible from the official website at open-std.org/jtc1/sc22/wg14/www/docs/n1570.pdf