Wei, Juncheng, Xuexiu Zhong, and Wenming Zou. “On Sirakov’s Open Problem and Related Topics”. ANNALI SCUOLA NORMALE SUPERIORE - CLASSE DI SCIENZE 23, no. 2 (June 23, 2022): 959-992. Accessed May 26, 2026. https://journals-dev.sns.it/index.php/annaliscienze/article/view/5429.