Here are my attaboys from years gone by…
Yes, there’s overlap between Max Planck IPP & ST-ECF (at ESO) (both at Garching, Munich). I did 2 jobs at once, both with the other’s approval.
Why none after 1993? I stopped asking for them. I think written testimonials are probably from a bygone era, nobody ever asked me for any. After all, that’s what references are for. My next job was at NASA GSFC; pity I didn’t get one from them, that would’ve been cool. But I started my own business then (in web design, one of the first such companies) and didn’t need a testimonial.