Mathematical Notes
Mathematical Notes > 2001 > 69 > 1-2 > 216-231
Mathematical Notes > 2006 > 79 > 1-2 > 41-54
Mathematical Notes > 2006 > 79 > 5 > 771-782
Mathematical Notes > 2006 > 79 > 5-6 > 771-782
Mathematical Notes > 2014 > 96 > 3-4 > 484-490
Mathematical Notes > 2015 > 98 > 5-6 > 714-724
Mathematical Notes > 2018 > 103 > 3-4 > 672-677