@Article{MC-11-2, author = {}, title = {封二}, journal = {数学文化}, year = {2020}, volume = {11}, number = {2}, pages = {0--0}, abstract = {}, issn = {2617-8656}, doi = {https://doi.org/2020-MC-16821}, url = {https://global-sci.com/article/89317/%E5%B0%81%E4%BA%8C} }