@Override
  public String toString() {
    return String.format("MusicRecording{id: %s, headline: %s, isrc: %s}",
        getIdentifier(), getHeadline(), getIsrcCode());
  }
POJO for https://schema.org/MusicRecording
portability-types-common/src/main/java/org/datatransferproject/types/common/models/playlists/MusicRecording.java