"ČNS IFPI" (in Czech). Hitparáda – Radio Top 100 Oficiální. IFPI Czech Republic. Note: Select 50. týden 2007 in the date selector. Retrieved April 22, 2021.
hitparadask.ifpicr.cz
"ČNS IFPI" (in Slovak). Hitparáda – Radio Top 100 Oficiálna. IFPI Czech Republic. Note: insert 200803 into search. Retrieved April 22, 2021.