@article{ADM_2019_28_2_a4,
     author = {Matthew St. Denis and Wai Ling Yee},
     title = {A simplified proof of the reduction point crossing sign formula for {Verma} modules},
     journal = {Algebra and discrete mathematics},
     pages = {195--202},
     publisher = {mathdoc},
     volume = {28},
     number = {2},
     year = {2019},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/ADM_2019_28_2_a4/}
}