@article {1292,
	title = {Polylog space compression, pushdown compression, and Lempel-Ziv are incomparable},
	journal = {Theory of Computing Systems},
	volume = {48},
	year = {2011},
	pages = {731-766},
	url = {http://webdiis.unizar.es/~elvira/research.html},
	author = {E. Mayordomo and P. Moser and S. Perifel}
}

