API:  http://id.who.int/icd/release/10/2010/B21
{
    "@context": "http://id.who.int/icd/contexts/contextForICD10Entity.json",
    "@id": "http://id.who.int/icd/release/10/2010/B21",
    "parent": [
        "http://id.who.int/icd/release/10/2010/B20-B24"
    ],
    "child": [
        "http://id.who.int/icd/release/10/2010/B21.0",
        "http://id.who.int/icd/release/10/2010/B21.1",
        "http://id.who.int/icd/release/10/2010/B21.2",
        "http://id.who.int/icd/release/10/2010/B21.3",
        "http://id.who.int/icd/release/10/2010/B21.7",
        "http://id.who.int/icd/release/10/2010/B21.8",
        "http://id.who.int/icd/release/10/2010/B21.9"
    ],
    "browserUrl": "http://apps.who.int/classifications/icd10/browse/2010/en#/B21",
    "code": "B21",
    "title": {
        "@language": "en",
        "@value": "Human immunodeficiency virus [HIV] disease resulting in malignant neoplasms"
    },
    "classKind": "category"
}