?url_ver=Z39.88-2004&rft_id=10.1007%2FBF02461847&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.au=Gragnani%2C+A.&rft.aulast=Gragnani&rft.aufirst=A.&rft.issue=5&rft.volume=57&rft.date=September+1995&rft.issn=1522-9602&rft.atitle=A+universal+bifurcation+diagram+for+seasonally+perturbed+predator-prey+models&rft.title=Bulletin+of+Mathematical+Biology&rft.pages=701-712&rft.genre=article