@Article{	  FleischerEtAl17tocs:short,
  author	= "Fleischer, Lukas and Kufleitner, Manfred and Lauser,
		  Alexander",
  title		= "The Half-Levels of the FO2 Alternation Hierarchy",
  journal	= "Theory Comput.\ Syst.",
  publisher	= "Springer",
  pages		= "352--370",
  volume	= "61",
  number	= "2",
  year		= "2017",
  doi		= "10.1007/s00224-016-9712-2"
}