Yu J-C, Zhang M-H, Yu L, Zhai L-P, Song X, Dong F-D, et al. Experiment of a novel four-spherical intrauterine contraceptive device with nickel-titanium. Clin J Obstet Gynecol [Internet]. 2020 Oct. 20 [cited 2025 Dec. 3];3(2):142-4. Available from: https://www.obstetricgynecoljournal.com/index.php/cjog/article/view/cjog-aid1068