@article{CMUC_1990__31_3_a20,
     author = {Soukup, Lajos},
     title = {A non-special $\omega_2$-tree with special $\omega_1$-subtrees},
     journal = {Commentationes Mathematicae Universitatis Carolinae},
     pages = {607--612},
     publisher = {mathdoc},
     volume = {31},
     number = {3},
     year = {1990},
     mrnumber = {1078493},
     zbl = {0711.03022},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMUC_1990__31_3_a20/}
}