@article{10_4064_fm_141_1_1_20,
     author = {Z. Ratajczyk},
     title = {Arithmetical transfinite induction and hierarchies of functions},
     journal = {Fundamenta Mathematicae},
     pages = {1--20},
     publisher = {mathdoc},
     volume = {141},
     number = {1},
     year = {1992},
     doi = {10.4064/fm-141-1-1-20},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/fm-141-1-1-20/}
}