[Tosyl1]

Can anyone suggest a decent book in potentiometry?
E.g., I am titrating iron (II) solution by adding dichromate. I am using four electrode setups:
Ag/AgCl reference electrode and nonpolarized Pt indicator electrode
Ag/AgCl reference eletrode and cathodically polarized Pt indicator electrode
Ag/AgCl reference eletrode and anodically polarized Pt indicator electrode
Two polarized Pt electrodes
I am not sure what are the benefits of any of these  
Any literature would be appreciated .
Thanks