?url_ver=Z39.88-2004&rft_id=10.1021%2Fol0272491&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.au=Rivkin%2C+A&rft.aulast=Rivkin&rft.aufirst=A&rft.issue=4&rft.volume=5&rft.date=20+February+2003&rft.issn=1523-7060&rft.atitle=Samarium(II)+iodide+mediated+radical%2Fpolar+crossover+reactions+of+cyclobutenes.+An+efficient+approach+to+the+BCD+ring+system+of+the+penitrems&rft.title=Organic+Letters&rft.pages=419+-+422&rft.genre=article