Zovi, samo zovi

"Zovi, samo zovi" (Serbo-Croatian for "Call, just call") is a Croatian and Serbian patriotic song. It is also known as "Oj Hrvatska mati" (lit. "Oh Croatia Our Mother") in Croatia and "Oj Srbijo mati" ("Oh Serbia Our Mother") in Serbia. It was most commonly known as "Jugoslavska mati" during the early days of Yugoslavia and served a similar purpose as La Marseillaise in France. 
The early lyrics ("zovi, samo zovi") originated during World War I and spread as a South Slav rallying cry, with the additional verses added later.
Origins.
The rise of Pan-Slavism in the 19th century led to calls for unity within the South Slavic people, including Serbs, Croats, and Slovenes. Proponents of the movement believed in unifying the South Slavic people through similarities in their language, culture, and ethnicity. It was during this time in Prague that the Sokol, or "falcon" movement was founded and quickly spread throughout the Slavic lands. The "Sokol" would become a popular motif in national songs and writings during both the times of Austria-Hungary and the Kingdom of Yugoslavia.
One of the earliest writings of the song were found in the 1919 journal "Jugoslavenska Njiva", where the local people were described as singing "Zovi, samo zovi" along with "Vive La France" and "La Marseillaise". Other lyrics were not combined together until years later. "Jugoslavska mati" ("Yugoslavia mother") appeared separately at first, then was combined with "zovi, samo zovi". Various regions of Yugoslavia were added into the lyrics, including those in Serbia, Croatia, Bosnia and Herzegovina, and Montenegro.
Croatian lyrics.
One of the early mentions of the lyrics "zovi samo zovi" comes from the writings of Croatian author Slavko Ježić in a 1923 publication describing the singing in the streets of Zagreb: "And indeed, out of the streets there was loud singing in the room: Call, just call! / All the falcons / Will give their life for you!" ("I doista, vani s ulice dopiralo je u sobu bučno pjevanje: Zovi, samo zovi! / Svi će sokolovi / Za te život dati!") In 1929, it is mentioned by writer and publisher Alfons Hribar in his book ("U vezu razmišljan o našoj narodnoj tragediji i đačkim nasim manifestacijama srpsko-hrvatske omladine "zovi samo zovi!" i narodni nas genij zove, jer je kucnuo odlučan čas, a mi Hrvati-") 
In popular culture.
The generic fans chant "Zovi, samo zovi" is included in FIFA World Cup 2002 video game, regardless of which national teams are playing the match.