R. Freund, L. Staiger, S. Ivanov:
"Going Beyond Turing with {P} Automata: Regular Observer {\(\omega\)}-Languages and Partial Adult Halting";
International Journal of Unconventional Computing, 12 (2016), 1; 51 - 69.
http://www.oldcitypublishing.com/journals/ijuc-home/ijuc-issue-contents/ijuc-volume-12-number-1-2016/ijuc-12-1-p-51-69/