Camper Van Beethoven/Cracker singer David Lowery has been at the forefront of many battles for artists’ financial rights, from the controversy over music streaming royalties to the ongoing problem of music piracy. Now, Lowery has found himself at the center of another battle, one over the publishing rights for song lyrics. The National Music Publishers Association is citing a study conducted by Lowery and the University of Georgia as the impetus behind 50 take-down notices issued to music lyric websites today.

Lowery’s study (which can be read here) concludes that a large number of websites that post song lyrics do so without obtaining the rights to those lyrics from their publishers. Lowery ranked the greatest offenders based on an “undesirability index.” Lowery’s undesirability index contains 50 offending websites that turn up as top results on search engines like Google or Bing.

“These lyric sites have ignored the law and profited off the songwriters’ creative works, and the NMPA will not allow this to continue,” NMPA chief David Israelite told The New York Times. “This is not a campaign against personal blogs, fan sites, or the many websites that provide lyrics legally. NMPA is targeting 50 websites that engage in blatant illegal behavior, which significantly impacts songwriters’ ability to make a living.”

Ilan Zechory, the co-founder of Lowery’s #1 “undesirable” website RapGenius, contacted the Times to claim that his site does more than merely re-post song lyrics. However, Zechory did not acknowledge whether or not RapGenius posts song lyrics without license.