Rønn, A, K M Nørgaard, and O Svendsen. 2000. “Effects of Pre- or Postoperative Morphine and of Preoperative Ketamine in Experimental Surgery in Rats, Evaluated by Pain Scoring and C-Fos Expression”. Scandinavian Journal of Laboratory Animal Science 27 (4):231-43. https://doi.org/10.23675/sjlas.v27i1.33.