A Leaf-Size Hierarchy of Two-Dimensional Alternating Turing Machines.

Katsushi Inoue Itsuo Takanami Juraj Hromkovic A Leaf-Size Hierarchy of Two-Dimensional Alternating Turing Machines. 99-110 1989 67 Theor. Comput. Sci. 1 db/journals/tcs/tcs67.html#InoueTH89