?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.au=+Dorr+John+Van+N.&rft.aulast=Dorr&rft.aufirst=John+Van+N.&rft.volume=19&rft.issn=0365-8066&rft.title=Acta+mineralogica-petrographica&rft.pages=221-226&rft.atitle=Letters+of+the+Working+Group+on+Manganese+Formations+of+the+International+Association+on+the+Genesis+of+Ore+Deposits+%3A+report+on+international+symposium+on+the+geology+and+genesis+of+Precambrian+iron+and+manganese+formations%2C+Kiev%2C+August%2C+19-25%2C+1970&rft.date=1970&rft.issue=2&rft.genre=article