@article{etna_vol45_pp33-57, author = {Luka Grubi\v{s}i\'{c} and Suzana Miodragovi\'{c} and Ninoslav Truhar}, title = {Double angle theorems for definite matrix pairs}, journal = {Electron. Trans. Numer. Anal.}, volume = {45}, year = {2016}, pages = {33--57}, }