The National Music Publishers Association delivered up to fifty take-down notices to unlicensed lyric sites this week, Billboard reported. Among the sites notified were Rap Genius (the New York startup that landed a $15 million investment from a Silicon Valley venture firm), lyricsdepot.com, e-chords.com, guitaretab.com, lybio.net, seeklyrics.com and many more.

The NMPA based their take-down notices after a report by University of Georgia researcher David Lowery, where Lowery confirmed that each site likely didn’t have licenses to publish lyrics. The notices demand that the sites obtain licensed or remove copyrighted lyrics from their sites. The group claims that more than five million searched for “lyrics” occur everyday on Google, and over 50% of all lyric page views are on unlicensed lyric sites.

“This is not a campaign against personal blogs, fan sites, or the many websites that provide lyrics legally,” NMPA Chief Executive David Israelite said. The NMPA is reportedly “targeting fifty sites that engage in blatant illegal behavior.”