How to drive 4-Digit 7-Segment LED Display with Arduino | MakBit Software
Amazon.com: uxcell Common Cathode 12 Pin 4 Bit 7 Segment Display 1.18 x 0.55 x 0.28 Inch 0.35" Red LED Display Digital Tube 2pcs : Industrial & Scientific
Using a 4 Digit & 7 Segment Display, With Arduino : 7 Steps - Instructables