any good books on cash games?

[lingdog]

hi every1, i m better than average at single table sit & go, i have been winning a little quite consistently. i am now thinking of playing some small stakes cash games, just a quick question, are cash games more profitable than sit & go? and what type of hold em cash games are easier to make profit? NL, Limit or PL? and what are the best books on cash games?
Thanks guys