[cctalk] Looking for Fred N van Kempen ... (pdp11, GUTS)

20 years ago I loaned Fred van Kempen a pdp11 disk pack (RK11?) to try recovering for me. We think it may have the Dutch "GUTS" operating system (Groningen University Timesharing System - https://gtoal.com/history.dcs.ed.ac.uk/archive/scans/guts/*.pdf ) and sources on it. My Dad carefully hand-carried it to the Netherlands from Scotland by boat and bicycle!, avoiding any magnetic scanning on the way. I never heard back from Fred and every now and then (some years apart) I try to contact him but all the mail addresses I've tried go unreplied or bounce. Does anyone here know him and have a reliable way to contact him? He might be in the USA now and the only indication I have that he's still alive is a github update in Jan of this year (and happily a lack of hits when looking for an obituary!). I'm assuming he never extracted the disk contents because if he had I'm sure he would have contacted me. If the disk has not degraded too much over the last 20 years since I last saw it, I'ld still like to recover it and so I'ld like to get it back from Fred and give it to whoever else might be able to read it. Thanks, Graham