the root isn't wet it is most peculiarly w t the long o is not the lengthened o grade of the short e in the ablaut system your author didn't like very well the long o is the germanic reflex of pre germanic long a w dinaz is proto germanic not pre germanic the pre germanic is w tinos the difference between the two also drives home the point of making a distinction between pre germanic and proto germanic as for the barred d for the proto germanic d phoneme that's just one possible convention for writing proto germanic take it up with our proto germanic article we should aim for some consistency across articles as for a source i agree that pokorny is just useful for an overview of non germanic cognates not for an in depth discussion of germanic etymology for that we have the perfectly academic recent and insightful article by r bekeil which has been referenced in plain views since about