@article{AMLG_1975__17_137904,
     author = {N. Georgieva},
     title = {On the decidability of p', p'' and p''*.},
     journal = {Archiv f\"ur mathematische Logik und Grundlagenforschung},
     pages = {51--54},
     publisher = {mathdoc},
     volume = {17},
     year = {1975},
     zbl = {0361.02058},
     url = {http://geodesic.mathdoc.fr/item/AMLG_1975__17_137904/}
}