Relation between purchline,VENDINVOICETRANS VENDPACKINGSLIPTRANS

I am not able to determine the relationship between these tables. I am getting duplicates. please help

if i can join VENDINVOICETRANS and VENDPACKINGSLIPTRANS . That would be great as well.

FROM dbo.PURCHLINE pl
LEFT OUTER JOIN dbo.VENDINVOICETRANS vt
           on pl.PURCHID = vt.ORIGPURCHID
         AND pl.ITEMID = vt.ITEMID
        AND pl.INVENTDIMID = vt.INVENTDIMID
LEFT OUTER JOIN dbo.VENDPACKINGSLIPTRANS vp
         AND pl.PURCHID = vp.ORIGPURCHID
        AND pl.ITEMID = vp.ITEMID
       AND pl.INVENTDIMID = vp.INVENTDIMID