Kjaer, M. and Nielsen, H. 1988. Analgesic Effect and Bioavailability of Oral Ketogan Given as Tablets or Mixture to Patients with Chronic Pain of Malignant Origin. Acta Oncologica. 27, 5 (Jan. 1988), 583–589. DOI:https://doi.org/10.3109/02841868809093593.