[R] how to get xlab and ylab in bold?

[Nevil Amos]

A very basic query

This code plots OK the axis values are in bold but the axis labels are 
not.  how do I get them in bold too?

thanks

Nevil Amos

plot(c(1,1),xlim=c(0,450),ylim=c(0.7,1.4),xlab="Distance (cells) from 
edge of grid",ylab="Resistance distance", 
type="l",col="white",lwd=2,font=2,family='sans')