@article{ZNSL_2000_270_a2,
     author = {B. Dittmar and A. Yu. Solynin},
     title = {Mixed {Stekloff} eigenvalue problem and new extremal properties of the {Gr\"otzsch} ring},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {51--79},
     publisher = {mathdoc},
     volume = {270},
     year = {2000},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_2000_270_a2/}
}