AD7707 and reference voltage

I want to use AD7707 for temperature measurement ("RTD.gif") and analog signals 0-5V and 0-10V ("Analog In.gif ").

What to use for reference voltage:
- AD780 ("REF.gif")
- resistor 6.25 kOm

If I use a resistor of 6.25 kOm, how can it affect the measurement of analog signals?