@InCollection{	  dr99book,
  author	= "Diekert, Volker and Robson, John Michael",
  title		= "Quadratic word equations",
  booktitle	= "Jewels are forever -- Contributions on Theoretical
		  Computer Science in Honor of Arto Salomaa",
  editor	= "Juhani Karhum{\"a}ki and Hermann Maurer and Gheorghe
		  P\u{a}un and Grzegorz Rozenberg",
  publisher	= "Springer-Verlag",
  pages		= "314--326",
  year		= "1999",
  doi		= "10.1007/978-3-642-60207-8_28"
}