{ "items" : [
    { "id" : "http://ns.inria.fr/covid19/PMC1831551#title"
      "properties" : {
        "http://purl.org/dc/terms/subject" : [ "Clinical research",
          "Causal inference",
          "Feces",
          "Conditions diagnosed by stool test",
          "Design of experiments"] } } }
