after introducing what he called "monster comics" in "monster world", warren expanded in 1964 with horror-comics stories in the sister magazines "creepy" and "eerie" – black-and-white publications in a standard magazine format, rather than comic-book size, and selling for 35 cents as opposed to the standard comic-book price of 12 cents. such a format, warren explained, averted the restrictions of the comics code authority, the comic-book industry's self-censorship body: