moved on to more modern pop forms, consigning the country's 1960s–1970s rock music to the memories of older fans who had survived the genocide. In the ensuing years, fans of Cambodian rock music found and reproduced the few records and master tapes that survived the chaos of the Khmer Rouge regime. A black market in remixed and reprinted works by popular but now-deceased (and some still-living) musicians developed, with little regard for intellectual property rights, which were not enforced in Cambodia until 2003. Black marketeers were known to remix songs by artists like Ros Serey Sothea and Pen Ran to make them more dance-able for current music fans, often with unknown musicians adding stronger drum beats and other effects; some songs were also artificially sped up so more could be squeezed onto inexpensive cassettes to be sold on the street. This unauthorized marketplace allowed Cambodian rock songs to remain popular well into the 1990s; original and authentic master recordings are highly sought by collectors and preservationists, though few are known to have survived the Khmer Rouge regime. The Cambodian rock genre of the 1960s–1970s remained largely unknown to the outside world until the late 1990s. While on a tourist trip to Cambodia in 1994, American Paul Wheeler became interested in music he had been hearing around Siem Reap. He purchased some unmarked cassettes from a market vendor and assembled a mixtape of his favorite tracks. The Parallel World label, upon hearing Wheeler's mixtape, assembled the 13-track compilation album Cambodian Rocks and released 1,000 copies on vinyl in 1996. When those sold out, the label issued the much more widely known CD version with 22 tracks. Wheeler made no effort to discover the song titles or the names of the artists, and Cambodian Rocks was released with no supporting information, thus giving it the appearance of a bootleg. In the years since the CD's release, interested listeners have collaborated on the Internet to confirm the artist names and song titles, discovering that ten of the album's 22 songs were by Ros Serey Sothea, with other tracks by Sinn Sisamouth, Pen Ran, Yol Aularong, Meas Samon, and Liev Tuk. Cambodian Rocks was widely praised by the Western rock community. Rolling Stone called it "a marvel of cultural appropriation," and Far East Audio called it an "instant classic." Further illustrating the unique nature of the music to Western ears, writer Nick Hanover called