- Grand Canyon tourists exposed to radiation, safety manager says. https://www.azcentral.com/story/news/local/arizona/2019/02/18/grand-canyon-tourists-exposed-radiation-safety-manager-says/2876435002/ 15 comments worldnews
- Grand Canyon tourists exposed to radiation, safety manager says https://www.azcentral.com/story/news/local/arizona/2019/02/18/grand-canyon-tourists-exposed-radiation-safety-manager-says/2876435002/ 5 comments nottheonion
- Grand Canyon tourists exposed to radiation, safety manager says https://www.azcentral.com/story/news/local/arizona/2019/02/18/grand-canyon-tourists-exposed-radiation-safety-manager-says/2876435002/ 12 comments worldnews