@article{PMFA_1970_15_2_a1,
     author = {Gr\"un, Marcel and Koubsk\'y, Pavel},
     title = {Pokroky kosmick\'e astronomie},
     journal = {Pokroky matematiky, fyziky a astronomie},
     pages = {62--76},
     year = {1970},
     volume = {15},
     number = {2},
     language = {cs},
     url = {http://geodesic.mathdoc.fr/item/PMFA_1970_15_2_a1/}
}