Today Springer has published a
new bibliography of the
Gesamtausgabe.
It'll cost you bitcoin 0.112 in US$, ฿ 0.126 in €, or ฿ 0.138 in £. I'd pay in greenbacks. An alternative is to use this
bibliography. It does not have the level of detail (pagination in
die Bände) but it is in HTML, which is a little easier to navigate than a PDF file.