The precise beginnings of the Bronze and Copper Ages remain less well-defined. Suggested starting points for the Bronze Age of comics include Roy Thomas and Barry Windsor-Smith's Conan No. 1 (October 1970), Denny O'Neil and Neal Adams' Green Lantern/Green Arrow No. 76 (April 1970), or Stan Lee and Gil Kane's The Amazing Spider-Man No. 96 (May 1971; the non-Comics Code issue). The start of the Copper Age (apprx. 1984–2000) has even more potential starting points, but is generally agreed to be the publication of Frank Miller's Batman: The Dark Knight Returns and Alan Moore's Watchmen by DC Comics in 1986, as well as the publication of DC's Crisis on Infinite Earths, written by Marv Wolfman with pencils by George Pérez.