RICCI-FLAT SPACES WITH A METRIC OF SPECIAL FORM ArticleKorrèa Kh., Ryzhkov V.V.Webs and quasigroups (Russian). 1990. P.. 95-97
THE SECOND BOUNDARY VALUE PROBLEM FOR A PARABOLIC DIFFERENTIAL-DIFFERENCE EQUATION ArticleSelitskiĭ A.M., Skubachevskiĭ A.L.Успехи математических наук. 2007.