Stromberg, Lars, Gunnar Öhlen, Conny Nordin, Urban Lindgren, and Olle Svensson. 1999. “Postoperative Mental Impairment in Hip Fracture Patients: A Randomized Study of Reorientation Measures in 223 Patients”. Acta Orthopaedica 70 (3):250-55. https://doi.org/10.3109/17453679908997801.