Gursoy Sinan, Ozdemir Ercan, Bagcivan Ihsan, Altun Ahmet, and Durmus Nedim. 2011. “Effects of Alpha 2-Adrenoceptor Agonists Dexmedetomidine and Guanfacine on Morphine Analgesia and Tolerance in Rats”. Upsala Journal of Medical Sciences 116 (4):238–246. https://doi.org/10.3109/03009734.2011.597889.