I haven't read either for a long time but I liked the 2+2 books, i think Ray Zee does stud 8 (combo with O8 but they are split) and sklansky stud high. I forget if there is a razz one, I do not own it. They are both old but I don't think these games change nearly as much as NLHE has.
the super systems have chapters. IIRC the stud '8' chapter in SS is just stud high low with no qualifier.