@article{PPR80, <br>AUTHOR = {Paul, W.J. and Prauss, E. and Reischuk, R.},<br>TITLE = {On Alternation},<br>VOLUME = {14}, <br>YEAR = {1980},<br>PAGES = {243--255}, <br>URL = {http:///publikationen/PPR80.pdf}, <br>SERIES = {Acta Informatica 1980},<br>EE = {http://www.springerlink.de/content/d6t6810300h2478p/},<br>}