Zhang, Dengshen, Shan Wei, Daxing Liu, and Yingqiang Guo. “Primary Osteosarcoma of Left Atrial Appendage in a Patient With Rheumatic Heart Disease”. The Heart Surgery Forum 25, no. 4 (July 27, 2022): E571-E573. Accessed August 14, 2022. https://journal.hsforum.com/index.php/HSF/article/view/4749.