And to be true DSD, they need to not just be recorded by a good DSD ADC, but also there must be no DXD step (PCM) that is required for usual mixing/mastering. Yet PCM mixing is done for most DSD releases, causing there to be very few pure DSD recordings, see:
https://www.grimmaudio.com/site/assets/files/1088/dsd_myth.pdf
http://www.mojo-audio.com/blog/dsd-vs-pcm-myth-vs-truth/
Or one can follow this best practice (quoted from the first link by Grimm Audio):
"Mix everything on an analogue desk, record the result digitally using a native 64 fs DSD converter (like Grimm Audio’s AD1). Don’t change any levels or other properties of the audio, except some crossfades where necessary, using special software that leaves the rest of the audio untouched (see above). The end result will be 99% pure DSD. Almost no one does that, Channel Classics may well be the only one in the trade. We should admire them for this and encourage them to issue their beautiful recordings in 64 fs for many years to come. And believe it or not, if they were to convert these recordings to 128 fs this would deteriorate the audio quality." (End quote.)
The best DSD recordings I've heard were recorded straight from R2R master tapes. Any mastering was done by analog equipment before the ADC. No digital mastering at all. Not too many recordings out there like that. There are some though.