 Collecting and identifying the overprints can be an arduous task as there are numerous variations in the overprint settings . Feldman states " the complex details of plating , shading , overprint colours , accurate measurements , to mention a few , often discourage even the most enthusiastic collector " . Three specialised books , or catalogue chapters , ( Freeman & Stubbs , Munk and Meredith ) , issued within five years of issue have concentrated on this topic and Meredith is regarded as unequalled . 
