Before revision:  Finally, we show that every graph has an additive 6W-spanner on O(n^{4/3}) edges where W is a constant}  .
After revision:  Finally, we show that every graph has an additive 6W-spanner on O(n^{4/3}) edges where W is a constant} . For a technical reason, the +6 unweighted spanner becomes a +8W weighted spanner; closing this error gap is an interesting remaining open problem .