Maybe it depends on your age

I know a lot of their songs, but from my childhood. I just went the first youtube playlist that came up when I put "Best of Crosby, Stills, Nash, and Young" into Youtube
Judy Blue Eyes, Long Time Gone, Just a Song Before I Go, and Southern Cross were the first 4 songs on the list, and I knew them all.
I don't know how much of their stuff was strictly from the Super Group and which was from previous projects. I think of Teach Your Children and Our House when it comes to them. Though, are those from CSN or CSNY? A super fan would probably know. I am definitely a casual folk fan at best. I like The Byrds, and Neil Young's solo stuff better.
Teach Your Children and Our House were both written by Graham Nash, but they first recorded them for the CSNY Deja Vu album in 1970, at least according to wikipedia