Peter Hertling. Is the Mandelbrot set computable? Mathematical
Logic Quarterly 2005 (51), 5 - 18.
Vasco Brattka. The emperor's new recursiveness: the epigraph of
the exponential function in two models of computability.
In: Masami Ito and Teruo Imaoka, editors, Words, Languages &
Combinatorics III, pp 63 - 72.
World Scientific Press
2003.