@techreport{LamMT11a,
  author = {R. Lamour and R. M{\"a}rz and C. Tischendorf},
  title = {Projector Based Analysis of Linear Differential--Algebraic Equations},
  institution = {Humboldt-University, Dep. of Mathematics},
  year = {2011},
  number = {11-20},
  url = {http://www2.mathematik.hu-berlin.de/publ/pre/2011/P-11-20.pdf}
}