49ers' George Kittle, Nick Bosa join NFL Twitter in calling for
NFL field surface intel: Grass vs. turf, owners, problems - ESPN
49ers' George Kittle calls for surface continuity among NFL
Seahawks coach Pete Carroll: Levi's Stadium grass is 'lousy'
49ers troubled turf gets first test Sunday against Cowboys at
San Francisco 49ers' turf wars continue in new Levi's Stadium
It is a joke!” – Jason and Travis Kelce slam NFL's turf fields
Kawakami: Nick Bosa's practical and powerful case against
Grass Valley City and School District Partner to Bring Year-Round
2021 Eastern Washington University Football Fact Book (posted July
NFL's 5 healthiest, most injured teams; inside turf vs. grass
Iowa State's Jack Trice Stadium remains only major college