Holland, like DKA, were so damned prolific, having upmixed tons of stereo. Both were members of our SBU group, and many other members contributed a lot as well. Much has been lost over the years, but a substantial amount remains from these two, and some from the rest of us, and a fair bit from EoH as well. I recently came into a very large amount of Holland's mixes, thanks to a friend.
The bulk of these upmixes were done many years ago, but some still hold up quite well.
These were done in the days before AI stem separation became available.
There's a long history here, of upmixing, that goes back to the early 2000's.
There were people that devised their own methods, such as GART, TOUP, etc.
Andreas sort of started the ball rolling on using Plogue Bidule, and he and Aart collaborated on methods with Andreas doing the research and devising the layouts. Later after we formed the SBU group, dts350z (Zeerround) did his own research, as well as combining multiple methods into SPEC. EoH (Aart ) eventually went his own way and concentrated more on methods of upmixing using some Ambisonic in his work.
All deserve credit. Glad I was along for the ride.