@article{SIGMA_2014_10_a90,
     author = {Adam Hlav\'a\v{c} and Michal Marvan},
     title = {A {Reciprocal} {Transformation} for the {Constant} {Astigmatism} {Equation}},
     journal = {Symmetry, integrability and geometry: methods and applications},
     year = {2014},
     volume = {10},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SIGMA_2014_10_a90/}
}