Question: When did the country Rīgas Balss is from become part of the Soviet Union?

full_context: Document 1: History of Latvia: The First Latvian National Awakening began in the 1850s and continued to bear fruit after World War I when, after two years of struggle in the Latvian War of Independence, Latvia finally won sovereign independence, as recognised by Soviet Russia in 1920 and by the international community in 1921. The Constitution of Latvia was adopted in 1922. Political instability and effects of the Great Depression led to the May 15, 1934 coup d'état by Prime Minister Kārlis Ulmanis. Latvia's independence was interrupted in June -- July 1940, when the country was occupied and incorporated into the Soviet Union. In 1941 it was invaded and occupied by Nazi Germany, then reconquered by the Soviets in 1944 -- 45.
Document 2: Molotov–Ribbentrop Pact: In mid-June 1940, when international attention was focused on the German invasion of France, Soviet NKVD troops raided border posts in Lithuania, Estonia and Latvia. State administrations were liquidated and replaced by Soviet cadres, in which 34,250 Latvians, 75,000 Lithuanians and almost 60,000 Estonians were deported or killed. Elections were held with single pro-Soviet candidates listed for many positions, with resulting peoples assemblies immediately requesting admission into the USSR, which was granted by the Soviet Union. The USSR annexed the whole of Lithuania, including the Scheschupe area, which was to be given to Germany.
Document 3: Russky Newsweek: Russky Newsweek or "Newsweek Russia" was a Russian language news magazine published in Russia between 2004 and 2010 as the Russian edition of "Newsweek". It was the first news magazine with a Western origin published in the country.
Document 4: List of newspapers in Bahrain: Bahrain's Information Affairs Authority reported that the number of newspapers in 1999 was four which were published in Arabic and English languages. There were a total of 12 dailies and weeklies in the country in 2012.
Document 5: Rīgas Balss: Rīgas Balss () was a tabloid newspaper published in Riga, Latvia, published in Latvian and Russian languages. The Russian edition has turned into "Vechernyaya Riga" in 2001 and ceased publication in 2004. Latvian edition has turned into journal in 2008 and ceased publication in 2009.
Document 6: Boston: The Boston Globe and the Boston Herald are two of the city's major daily newspapers. The city is also served by other publications such as Boston magazine, The Improper Bostonian, DigBoston, and the Boston edition of Metro. The Christian Science Monitor, headquartered in Boston, was formerly a worldwide daily newspaper but ended publication of daily print editions in 2009, switching to continuous online and weekly magazine format publications. The Boston Globe also releases a teen publication to the city's public high schools, called Teens in Print or T.i.P., which is written by the city's teens and delivered quarterly within the school year.
Document 7: Ann Arbor, Michigan: The Ann Arbor News, owned by the Michigan-based Booth Newspapers chain, is the major daily newspaper serving Ann Arbor and the rest of Washtenaw County. The newspaper ended its 174-year print run in 2009, due to economic difficulties. It was replaced by AnnArbor.com, but returned to a limited print publication under its former name in 2013. Another Ann Arbor-based publication that has ceased production was the Ann Arbor Paper, a free monthly. Ann Arbor has been said to be the first significant city to lose its only daily paper. The Ann Arbor Chronicle, an online newspaper, covered local news, including meetings of the library board, county commission, and DDA until September 3, 2014.
Document 8: Dissolution of the Soviet Union: On June 14, 1987, about 5,000 people gathered again at Freedom Monument in Riga, and laid flowers to commemorate the anniversary of Stalin's mass deportation of Latvians in 1941. This was the first large demonstration in the Baltic republics to commemorate the anniversary of an event contrary to official Soviet history. The authorities did not crack down on demonstrators, which encouraged more and larger demonstrations throughout the Baltic States. The next major anniversary after the August 23 Molotov Pact demonstration was on November 18, the date of Latvia’s independence in 1918. On November 18, 1987, hundreds of police and civilian militiamen cordoned off the central square to prevent any demonstration at Freedom Monument, but thousands lined the streets of Riga in silent protest regardless.
Document 9: Estonia: In 1989, during the "Singing Revolution", in a landmark demonstration for more independence, more than two million people formed a human chain stretching through Lithuania, Latvia and Estonia, called the Baltic Way. All three nations had similar experiences of occupation and similar aspirations for regaining independence. The Estonian Sovereignty Declaration was issued on 16 November 1988. On 20 August 1991, Estonia declared formal independence during the Soviet military coup attempt in Moscow, reconstituting the pre-1940 state. The Soviet Union recognised the independence of Estonia on 6 September 1991. The first country to diplomatically recognise Estonia's reclaimed independence was Iceland. The last units of the Russian army left on 31 August 1994.
Document 10: Vokrug sveta: Vokrug sveta (, literally: "Around the World") is a Russian geographic magazine. It is the longest running magazine in the Russian language. The first issue was printed in Saint Petersburg, in December 1861, almost thirty years before the establishment of the "National Geographic Magazine". Thus, it is one of the oldest popular science magazines in the world. Release of "Vokrug sveta" was suspended twice: from 1918 to 1927, during the Russian Revolution, and from 1941 to 1945, during World War II. Nevertheless, the magazine always resumed and continues to be published to this day.
Document 11: Estonia: On 6 August 1940, Estonia was annexed by the Soviet Union as the Estonian SSR. The provisions in the Estonian constitution requiring a popular referendum to decide on joining a supra-national body were ignored. Instead the vote to join the Soviet Union was taken by those elected in the elections held the previous month. Additionally those who had failed to do their "political duty" of voting Estonia into the USSR, specifically those who had failed to have their passports stamped for voting, were condemned to death by Soviet tribunals. The repressions followed with the mass deportations carried out by the Soviets in Estonia on 14 June 1941. Many of the country's political and intellectual leaders were killed or deported to remote areas of the USSR by the Soviet authorities in 1940–1941. Repressive actions were also taken against thousands of ordinary people.
Document 12: Boston: The city's growing Latino population has given rise to a number of local and regional Spanish-language newspapers. These include El Planeta (owned by the former publisher of The Boston Phoenix), El Mundo, and La Semana. Siglo21, with its main offices in nearby Lawrence, is also widely distributed.
Document 13: Latvian Soviet Socialist Republic: Following the Welles Declaration of July 23, 1940, the annexation of Latvia into the Soviet Union (USSR) on 5 August 1940 was not recognized as legitimate by the United States, the European Community, and recognition of it as the nominal fifteenth constituent republic of the USSR was withheld for five decades. Its territory was subsequently conquered by Nazi Germany in June -- July 1941, before being retaken by the Soviets in 1944 -- 1945. Nevertheless, Latvia continued to exist as a de jure independent country with a number of countries continued to recognize Latvian diplomats and consuls who still functioned in the name of their former governments.
Document 14: Post-Soviet states: The post-Soviet states, also collectively known as the former Soviet Union (FSU) or former Soviet Republics, are the 15 independent states that emerged from the Union of Soviet Socialist Republics in its dissolution in December 1991, with Russia internationally recognised as the successor state to the Soviet Union. On March 11, 1990, Lithuania was the first to declare its independence, with Estonia and Latvia following suit in August 1991. All three Baltic states claimed continuity from the original states that existed prior to their annexation by the Soviet Union in 1944 and were admitted to the United Nations on 17 September 1991. The remaining 12 republics all subsequently seceded. 12 of the 15 states, excluding the Baltic states, initially formed the CIS and most joined CSTO, while the Baltic states focused on European Union and NATO membership.
Document 15: Russian language: According to figures published in 2006 in the journal "Demoskop Weekly" research deputy director of Research Center for Sociological Research of the Ministry of Education and Science (Russia) Arefyev A. L., the Russian language is gradually losing its position in the world in general, and in Russia in particular. In 2012, A. L. Arefyev published a new study "Russian language at the turn of the 20th-21st centuries", in which he confirmed his conclusion about the trend of further weakening of the Russian language in all regions of the world (findings published in 2013 in the journal "Demoskop Weekly"). In the countries of the former Soviet Union the Russian language is gradually being replaced by local languages. Currently the number speakers of Russian language in the world depends on the number of Russians in the world (as the main sources distribution Russian language) and total population Russia (where Russian is an official language).
ground_truth: 5 August 1940
sub_queries: What is the country Rīgas Balss is from? Answer: Latvia
when did Latvia become part of the soviet union Answer: 5 August 1940