@article {Bertola:Duality, title = {The duality of spectral curves that arises in two-matrix models}, journal = {Teoret. Mat. Fiz.}, volume = {134}, number = {1}, year = {2003}, pages = {32{\textendash}45}, issn = {0564-6162}, author = {Marco Bertola and B. Eynard and Kharnad, Dzh.} }