It's just a general principle that money you "receive" as part of buying the house lowers your cost. That applies to the listed examples like abstract fees and transfer taxes, but it would also apply to non-listed items like a rebate of the real estate commission for example, or if the bank rebated the mortgage application fee if you met certain conditions in some kind of advertised promotion. (The publication is giving examples, not a comprehensive list.) Lowering your cost accounts for the taxability of the income without actually having to report it as taxable income.
If you want a specific reference for rent-backs, you probably need to look for something like a tax court case, Lasser's tax guide or an article in the Journal of Accountancy or some such. Maybe
@Critter#2 or
@Hal_Al can make a suggestion. I just think you are over thinking this.
