The form of LOCAL-URL depends on the position of the target file target.html relative to the source file.
SRC
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source.html target.html
SRC
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source.html BILL
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FRED target.html
N.B. subsubdirectory FRED would be BILL/FRED/ and so on..
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SRC target.html
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source.html
N.B. grandparent directory is "../../"; greatgranparent is "../../../" etc.