1. A method of deriving a schematic diagram representative of an integrated circuit (IC) comprising a plurality of circuit elements, the method comprising the steps of: receiving as input a working schematic diagram identifying at least some of the circuit elements, and at least one existing schematic diagram from one or more libraries thereof; automatically identifying at least a portion of the working schematic diagram that matches at least a portion of the at least one existing schematic diagram; and replacing the identified portion from the working schematic diagram with the matching portion from the at least one existing schematic diagram, thereby forming a revised schematic diagram.