title: Letter to the editor.
mesh_terms: D002219:Carbamates; D009603:Nitroso Compounds; D009607:Nitrosourea Compounds; D009626:Terminology as Topic; D014508:Urea; D014520:Urethane
chemical_list: D002219:Carbamates; D009603:Nitroso Compounds; D009607:Nitrosourea Compounds; D014520:Urethane; D014508:Urea