Contra (series) (English Wikipedia)

"CONTRA > CONVERSIONS > DOS". Contra Encyclopedia. June 30, 2014. Retrieved April 30, 2016.
"CONTRA > CONVERSIONS > CPC". Contra Encyclopedia. June 30, 2014. Retrieved April 30, 2016.
"CONTRA > CONVERSIONS > SPECTRUM". Contra Encyclopedia. June 30, 2014. Retrieved April 30, 2016.

disgruntleddesigner.com

"Arc Hound preview". Famicom Tsūshin (in Japanese). June 28, 1991. Archived from the original on December 11, 2017. Retrieved April 11, 2022.

KONAMI ANNOUNCES CONTRA 4 FOR NINTENDO DS™ (PDF), June 20, 2007, archived from the original (PDF) on April 10, 2022, retrieved April 10, 2022

"How To Play Contra (NES Manual)" (PDF). Games Database. Retrieved October 26, 2014.

Nintendo Player's Guide: Super NES. 1992. p. 152. Archived from the original on June 13, 2007. Retrieved August 13, 2007.

Hatfield, Daemon (May 12, 2009). "Contra ReBirth Impressions". IGN. Retrieved May 13, 2009.

IGN staff (January 29, 1999). "Contra Canned". IGN.com. Retrieved December 24, 2008.

Daemon Hatfield (June 3, 2010). "E3 2010: (Contra) Hard Corps Preview - PlayStation 3 Preview at IGN". Ps3.ign.com. Retrieved December 31, 2010.

"China's getting a Contra remake - Contra Database". www.klustr.net. Archived from the original on February 18, 2014. Retrieved April 30, 2016.
"The recurring bosses of Contra - Part 6". Contra Database. Retrieved October 26, 2014.
"The recurring bosses of Contra - Part 7". Contra Database. Retrieved October 26, 2014.

James Charlton (May 9, 2009). "Konami Announces Contra Rebirth for WiiWare". Nintendo World Report. Retrieved May 11, 2009.

"China's getting a Contra remake - Contra Database". www.klustr.net. Archived from the original on February 18, 2014. Retrieved April 30, 2016.
Operation C - Nintendo Game Boy - Manual - gamesdatabase.org (PDF), archived from the original (PDF) on April 10, 2022, retrieved April 10, 2022
KONAMI ANNOUNCES CONTRA 4 FOR NINTENDO DS™ (PDF), June 20, 2007, archived from the original (PDF) on April 10, 2022, retrieved April 10, 2022
Konami. Crisis Force (Family Computer) (in Japanese). Level/area: Pamphlet included with the game.
"Arc Hound preview". Famicom Tsūshin (in Japanese). June 28, 1991. Archived from the original on December 11, 2017. Retrieved April 11, 2022.
Nintendo Player's Guide: Super NES. 1992. p. 152. Archived from the original on June 13, 2007. Retrieved August 13, 2007.