@article{oai:tsukuba.repo.nii.ac.jp:00043511,
 author = {Asai, Yasutomo},
 issue = {1},
 journal = {Tsukuba Journal of Mathematics},
 month = {},
 pages = {79--97},
 title = {Loop groups SL₂(F[X,X⁻¹]), universal central extensions and additive Steinberg symbols},
 volume = {36},
 year = {2012}
}