Hello Katy Tour (English Wikipedia)

Kilgore, Kym (November 11, 2008). "Katy Perry takes 'Boys' along on headlining outing". liveDaily. Archived from the original on February 2, 2009. Retrieved March 3, 2009.
kayian, Suzanne (September 25, 2009). "Katy Perry, Leona Lewis, LL Cool J headline Grammy tour". liveDaily. Archived from the original on February 28, 2009. Retrieved February 28, 2009.

minneapolisfed.org

Carter, Don (February 27, 2009). "2009 Schaeffer Eye Center Crawfish Boil Lineup". WVTM. Birmingham Broadcasting (WVTM-TV), Inc. Retrieved February 28, 2009.^{[permanent dead link]}

"Katy Perry announces lengthy North American tour". NME. November 11, 2008. Retrieved November 11, 2008.

"Line Up". Oxegen Festival. Archived from the original on February 28, 2009. Retrieved March 3, 2009.

"Katy Perry". Pinkpop 2009. Archived from the original on March 9, 2009. Retrieved March 10, 2009.

"Katy Perry". Rock Werchter. Archived from the original on March 8, 2009. Retrieved March 3, 2009.

"Katy Perry". Southside Festival (in German). Archived from the original on April 9, 2009. Retrieved March 3, 2009.

"White Diamond Party". Club Skirts. Archived from the original on February 26, 2009. Retrieved March 12, 2009.

"2009 Line Up". T in the Park 2009. Archived from the original on February 28, 2009. Retrieved March 3, 2009.

"Review: "Katy Perry"". Variety. January 31, 2009. Retrieved September 25, 2013.

"Coming home to S.B., Perry bids farewell to 'Hello Katy Tour'". Ventura County Star. Scripps. August 31, 2009. Retrieved October 15, 2013.

"2009 Line Up". V Festival 2009. Archived from the original on September 28, 2009. Retrieved 2009-03-03.

"Events". katyperry.com. Archived from the original on 2009-02-28. Retrieved 2009-03-03.
Kilgore, Kym (November 11, 2008). "Katy Perry takes 'Boys' along on headlining outing". liveDaily. Archived from the original on February 2, 2009. Retrieved March 3, 2009.
"White Diamond Party". Club Skirts. Archived from the original on February 26, 2009. Retrieved March 12, 2009.
kayian, Suzanne (September 25, 2009). "Katy Perry, Leona Lewis, LL Cool J headline Grammy tour". liveDaily. Archived from the original on February 28, 2009. Retrieved February 28, 2009.
"Katy Perry". Pinkpop 2009. Archived from the original on March 9, 2009. Retrieved March 10, 2009.
"Katy Perry". Hurricane Festival (in German). Archived from the original on April 13, 2009. Retrieved March 3, 2009.
"Katy Perry". Southside Festival (in German). Archived from the original on April 9, 2009. Retrieved March 3, 2009.
"Katy Perry". Rock Werchter. Archived from the original on March 8, 2009. Retrieved March 3, 2009.
"2009 Line Up". T in the Park 2009. Archived from the original on February 28, 2009. Retrieved March 3, 2009.
"Line Up". Oxegen Festival. Archived from the original on February 28, 2009. Retrieved March 3, 2009.
"2009 Line Up". V Festival 2009. Archived from the original on September 28, 2009. Retrieved 2009-03-03.