@article { author = {}, title = {Cover for Vol. 13, No. 1.}, journal = {Categories and General Algebraic Structures with Applications}, volume = {13}, number = {1}, pages = {-}, year = {2020}, publisher = {Shahid Beheshti University}, issn = {2345-5853}, eissn = {2345-5861}, doi = {}, abstract = {}, keywords = {}, url = {https://cgasa.sbu.ac.ir/article_87550.html}, eprint = {https://cgasa.sbu.ac.ir/article_87550_62feec11c5bb913a40e10e34a343e4c1.pdf} }