@article{ITA_1983__17_1_49_0,
     author = {Calude, Cristian and P\u{a}un, Gheorghe},
     title = {Independent instances for some undecidable problems},
     journal = {RAIRO. Informatique th\'eorique},
     pages = {49--54},
     publisher = {EDP-Sciences},
     volume = {17},
     number = {1},
     year = {1983},
     mrnumber = {701987},
     zbl = {0517.03022},
     language = {en},
     url = {http://www.numdam.org/item/ITA_1983__17_1_49_0/}
}