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Total citations
| Country | Total citations |
|---|---|
| United States | 160802 |
| United Kingdom | 47533 |
| Brazil | 25876 |
| France | 21301 |
| Germany | 19619 |
| Canada | 18496 |
| Switzerland | 14069 |
| Spain | 10219 |
| India | 9910 |
| Italy | 7214 |
| Australia | 6812 |
| Japan | 6742 |
| Netherlands | 6705 |
| Israel | 6148 |
| Venezuela | 5037 |
| Belgium | 4895 |
| Kenya | 3417 |
| Sudan | 3417 |
| Sweden | 2794 |
| Denmark | 2657 |
| Colombia | 2424 |
| Argentina | 1954 |
| Iran | 1370 |
| Portugal | 1356 |
| Mexico | 1239 |
