@article{PR80, <br>AUTHOR = {Paul, W.J. and Reischuk, R.},<br>TITLE = {On Alternation II},<br>VOLUME = {14}, <br>YEAR = {1980},<br>PAGES = {391--403}, <br>SERIES = {Acta Informatica 1980},<br>EE = {http://www.springerlink.com/content/g5513071x065742h/},<br>}