8GB (1x8GB) DDR3-1600MHz PC3-12800 2Rx8 SODIMM Laptop Memory by NEMIX RAM at Amazon.com
OWC 16GB (2x8GB) ram Upgrade PC3-12800 DDR3L 1600MHz sodimm 204 Pin CL11 Memory Upgrade Kit Compatible with Late iMac, Mac Mini, and MacBook Pro Computer at Amazon.com
PC3-10600 DDR3 1333 8GB Kit (2x4GB) RAM PC3 10600S 1333MHZ 2Rx8 204-pin 1.5v 4GB Memory Upgrade for Laptop at Amazon.com