REVIEW: 8804 LEGO Minifigures Series 4 - Special LEGO Themes - Eurobricks Forums
LEGO Series 4 Collectible Minifigs from 2011 reviewed! - YouTube
BrickLink - Set col04-11 : LEGO Soccer Player, Series 4 (Complete Set with Stand and Accessories) [Collectible Minifigures:Series 4 Minifigures] - BrickLink Reference Catalog