title: Only the fittest survive.
authors: T
authors: T
authors: Sheldon
mesh_terms: D003695:Delivery of Health Care / Q000191:economics*; D006801:Humans; D011044:Poland; D011634:Public Health / Q000706:statistics & numerical data; D011787:Quality of Health Care / Q000191:economics*; D012924:Social Conditions; D012959:Socioeconomic Factors