@article{10_21136_CMJ_1970_100940,
     author = {Tom\'a\v{s}ek, Stanislav},
     title = {On a certain class of $\Lambda$-structures. {I}},
     journal = {Czechoslovak Mathematical Journal},
     pages = {1--18},
     publisher = {mathdoc},
     volume = {20},
     number = {1},
     year = {1970},
     doi = {10.21136/CMJ.1970.100940},
     mrnumber = {0268642},
     zbl = {0193.51202},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.21136/CMJ.1970.100940/}
}