@inproceedings{PPR78, <br>AUTHOR = {Paul, W.J. and Prauss, E. and Reischuk, R.},<br>TITLE = {On Alternation},<br>YEAR = {1978},<br>PAGES = {113--122}, <br>URL = {http:///publikationen/PPR78.pdf}, <br>BOOKTITLE = {Proc. 19th IEEE-FOCS}, <br>EE = {http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=4567969},<br>}