%0 Journal Article %A P. N. Brusov %A T. V. Filatova %T How to distinguish a mixture of two $d$-wave states from a pure $d$-wave state of high-temperature superconductors %J Contemporary Mathematics and Its Applications %D 2015 %P 102-111 %V 96 %I mathdoc %U http://geodesic.mathdoc.fr/item/CMA_2015_96_a6/ %G ru %F CMA_2015_96_a6