sorry for the long post but I should recommend a few places to look up this stuff.
Phil Davis wrote one of the best manuals on colour theory that has all this info in it. I use it in photo school but unfortunately lost my copie
Kodak has many manuals on colour therory and colour ring arounds.
start with these two sources, there are probably many others but remember..
the proper ring around does include subtractive colours mixed with additive colours to produce a second colour( yellow Magenta) -warm
as well it also includes an subtractive and additive colour (yellow green)
this is where it gets tricky and hard to tell the colours apart unless you have the chart
Thank you very much Bob, it does indeed help making a colour ring around and after a day or so working hard at it my knowledge has increased tenfold. Much appreciated.