title: Letter: Design of clinical trials.
mesh_terms: D000959:Antihypertensive Agents / Q000627:therapeutic use*; D001262:Atenolol / Q000627:therapeutic use*; D002986:Clinical Trials as Topic; D006801:Humans; D010919:Placebos; D011412:Propanolamines / Q000627:therapeutic use*; D012107:Research Design
chemical_list: D000959:Antihypertensive Agents; D010919:Placebos; D011412:Propanolamines; D001262:Atenolol