@article{UM_2009__17_2_a1,
     author = {Sm\'ykalov\'a, Radka},
     title = {Z historie goniometrick\'ych funkc{\'\i} - {Ptolemaiovy} v\'ypo\v{c}ty},
     journal = {U\v{c}itel matematiky},
     pages = {66--80},
     publisher = {mathdoc},
     volume = {17},
     number = {2},
     year = {2009},
     language = {cz},
     url = {http://geodesic.mathdoc.fr/item/UM_2009__17_2_a1/}
}