?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.aufirst=T&rft.au=Betcke%2C+T&rft.aulast=Betcke&rft.volume=435&rft.atitle=Perturbation%2C+extraction+and+refinement+of+invariant+pairs+for+matrix+polynomials&rft.issue=3&rft.date=1+August+2011&rft.pages=514-536&rft.title=Linear+Algebra+and+its+Applications&rft.issn=0024-3795&rft.genre=article