I just came across this information about released singles by the PSS.
They were released by Certron in 1970

Apartment Number Nine / Comin' Apart
Strawberry Fields Forever - Something / There's Never Been A Time - 70
Bringing It Down To You / He's A Friend Of Mine - 70

Does this make any sense to the PSS experts :-) ? Could this information be right? I don't know a lot about the Pozo's, because it's hard to get any material about them. The songs I have, are 'Don Williams - featuring the PSS', like the songs 14-18 listed in the previous message. I'm more like a Don Williams-solocareer expert :-).
Anja