レコード協会調べ 4月度有料音楽配信認定<略称:4月度認定> [Record Association report: April digital music download certifications (Abbreviation: April Certifications)]. RIAJ (in Japanese). May 20, 2011. Retrieved May 20, 2011.
レコード協会調べ 2月度有料音楽配信認定 <略称:2月度認定> [Record Association report: February digital music download certifications (Abbreviation: February Certifications)]. RIAJ (in Japanese). March 25, 2011. Retrieved March 25, 2011.
レコード協会調べ 6月度有料音楽配信認定<略称:6月度認定> [Record Association report: June digital music download certifications (Abbreviation: June Certifications)]. RIAJ (in Japanese). July 20, 2011. Retrieved August 5, 2011.