HP Service Notes - where are they?

[HalFoster]

While it is very easy to find HP's older Application Notes, Bench Briefs and such online, there are very few service notes floating around (including the ones sometimes available on the Keysight website) the vast majority are, as far as I can tell, not available either digitally of in print.  I see so many referenced in Bench Briefs and other places but have never been able to find more than a few.  Does anyone know if any more are available somewhere?  Keysight has some here, but not many.  Maybe just newer ones?

https://servicenotes.literature.keysight.com/litapp/SearchSN.do?method=openExternalSNSearch


Thank you,

Hal