Liu YF, Wu LA, Wang J, Wen LY, Wang XJ. Micro-computerized tomography analysis of alveolar bone loss in ligature- and nicotine-induced experimental periodontitis in rats. J Periodontal Res. 2010 Dec;45(6):714–9. doi: 10.1111/j.1600-0765.2010.01290.x. PMID: 20572916.