{ "items" : [
    { "id" : "http://ns.inria.fr/covid19/PMC5547245#title"
      "properties" : {
        "http://purl.org/dc/terms/subject" : [ "Social media",
          "Depression (mood)",
          "Natural language processing",
          "Abnormal psychology",
          "Affective computing",
          "Child and adolescent psychiatry",
          "Polling"] } } }
