California recalls cannabis vape months after it was told of contamination Los Angeles Times Cannabis Vaporizers vs Vape Pens: Know The Difference RQS Blog Marijuana and Vaping: Shadowy Past, Dangerous Present The New York Times What Happens When You Bring Marijuana Legally Purchased in Colorado or Oklahoma to Denton? Criminal Defense Attorney Denton Dan Peugh Zombie' drug xylazine found in cannabis THC vapes in UK BBC News Cannabis conundrum: Legal isn't always clean, nor illicit dirty Los Angeles Times