- Alabama Is Trying Nitrogen Hypoxia, an Untested Execution Method The New York Times
- Death penalty: Prisoner set to be first person in US executed using nitrogen gas | BBC News BBC News
- Alabama calls nitrogen execution method ‘painless’ and ‘humane,’ but critics raise doubts ABC News
- Guest opinion: Rage and the Alabama execution of Kenneth Smith by the new method of nitrogen hypoxia AL.com
- Alabama plans the first nitrogen gas execution this week in largely secret process experts say raises concerns about cruelty CNN