Uniformisation of color scale in different subplots with different limits

I have the following plot:

x=(1:10)';
y=(2:2:20)'

for k=1:10
    for r=1:10
     z1(k,r)=(5*k)+(4*r)+5;
     z2(k,r)=(5*k)-(4*r)-5;
    end
end
subplot(1,2,1)
surf(x,y,z1)
colorbar
subplot(1,2,2)
surf(x,y,z2)
colorbar

Now, the question is: How do I define a single color bar with unique and common maximum and minimum values (e.g. by fixing the upper and lower limits, as we can do it for the axis)? Thanks for your help and best regards.

[Luffy]

 see doc colorbar,on how to set Y Tick Labels.

[Teja Muppirala]

As described here, you can use the CAXIS command to manually set the color limits:

http://www.mathworks.com/matlabcentral/answers/39662-colorbar-cdata-and-colors