@PhDThesis{	  Weiss15diss,
  author	= "Armin Wei{\ss}",
  school	= "Institut f{\"u}r {F}ormale {M}ethoden der {I}nformatik,
		  {U}niversit{\"a}t {S}tuttgart",
  type		= "Dissertation",
  title		= "On the Complexity of Conjugacy in Amalgamated Products and
		  HNN Extensions",
  year		= "2015"
}