OWC 4GB PC12800 DDR3L 1600MHz SO-DIMM Memory Compatible with 2011-2015 iMac, 2011-12 Mac Mini, and 2011-2012 MacBook Pro (Non-Retina Display) Models (OWC1600DDR3S4GB) at Amazon.com
Apple 8GB Memory Kit (2x4GB) DDR3-1600MHz PC3-12800 SODIMM for MacBook Pro at Amazon.com