[R] ylab on secondary y axis

[Hai Lin]

Dear R users:

I am trying to add a label on axis(4) but I don't find
any reference in R archives. Could you please help me
out?

Thanks in advance.

The followings are the data set and what I have done:

Sample data:

time	 y1 y2
2	9 24.396
4	7.667 19.082	
10	4.667 73.984

Commands:
plot(time,y1,type='l',col='red',ylab="Relative
levels", xlab="Age of Mice",ylim=c(0,20))
points(time,y1 col="red", pch=19)

op <-par(new=T)
plot(time,y2,type='l',
col='green',axes=F,xlab="",ylab="", ylim=c(0,80))
points(time,y2,col='green',pch=24)
axis(4)