@article{10_4064_cm_30_1_1_5,
     author = {Kenneth A. Bowen},
     title = {Primitive recursive notations for infinitary formulas},
     journal = {Colloquium Mathematicum},
     pages = {1--5},
     publisher = {mathdoc},
     volume = {30},
     number = {1},
     year = {1974},
     doi = {10.4064/cm-30-1-1-5},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/cm-30-1-1-5/}
}