| Participation of the endogenous opioid and cannabinoid systems in neuropathic pain | 3 |
| 11 / 2012 | 12 / 2012 | 01 / 2013 | 02 / 2013 | 03 / 2013 | 04 / 2013 | 05 / 2013 | |
| Participation of the endogenous opioid and cannabinoid systems in neuropathic pain | 0 | 0 | 1 | 1 | 0 | 1 | 0 |
| 1 | Spain | 1 |
| 2 | Taiwan | 1 |
| 3 | United States of America | 1 |
| 1 | Sayreville | 1 |
| 2 | Sevilla | 1 |