https://scholar.google.com/citations?view_op=view_citation&hl=en&user=TWofD7kAAAAJ&citation_for_view=TWofD7kAAAAJ:u5HHmVD_uO8C
https://scholar.google.com/citations?view_op=view_citation&hl=en&user=TWofD7kAAAAJ&citation_for_view=TWofD7kAAAAJ:u-x6o8ySG0sC
https://scholar.google.com/citations?view_op=view_citation&hl=en&user=TWofD7kAAAAJ&citation_for_view=TWofD7kAAAAJ:9yKSN-GCB0IC