@Article{JMS-49-0, author = { }, title = { Preface}, journal = {Journal of Mathematical Study}, year = {2016}, volume = {49}, number = {4}, pages = {0--0}, abstract = {}, issn = {2617-8702}, doi = {https://doi.org/}, url = {http://global-sci.org/intro/article_detail/jms/10115.html} }