Article snapshot taken from Wikipedia with creative commons attribution-sharealike license.
Give it a read and then ask your questions in the chat.
We can research this topic together.
The union of Bukovina with Romania was declared in 28 November 1918, being officially recognized by the international community in 1919 and 1920.
4 November - Aurel Onciul, a Romanian Bukovinian politician, concludes an agreement (not authorized by the Romanian National Council) with the Ukrainian National Committee providing for the division of Bukovina along ethnic lines and joint Romanian-Ukrainian control over Czernowitz (the capital of Bukovina).
6 November - The Ukrainian National Committee occupies all Government buildings in Czernowitz and Omelian Popowicz is proclaimed President of "Ukrainian Bukovina".
7 November - Iancu Flondor appeals to the Romanian Government to occupy the entire land of Bukovina.
12 November - The Romanian National Council establishes a new government in Bukovina under Flondor's presidency.
28 November - The Romanian National Council, together with Polish and German representatives, convokes the General Congress of Bukovina which requests the union of Bukovina with Romania.
19 December - The Romanian Government issues a decree formalizing Bukovina's annexation.
1919
10 September - The Treaty of Saint-Germain-en-Laye is signed, recognizing Romanian sovereignty over Bukovina (the frontiers of Romania were to be later fixed).
1920
10 August - The Treaty of Sèvres established the Romanian-Polish boundary (mainly, based on the July 1919 Lwów Convention).
Aftermath
Since 2015, Bukovina Day is celebrated in Romania every 28 November to commemorate the union of the region with Romania.
Gallery
Bukovina within Austria-Hungary
Flag of Bukovina
Division of Bukovina (orange) as claimed by the West Ukrainian People's Republic (black interrupted line)
Ethnic map of Bukovina (purple = Romanians, green = Ukrainians)
^ Robert A. Kann, Zdenek David, University of Washington Press, 2017, Peoples of the Eastern Habsburg Lands, 1526-1918, p. 446
Vasyl Kuchabsky, Gus Fagan, Wirth-Institute for Austrian and Central European Studies, Canadian Institute of Ukrainian Studies Press, 2009, Western Ukraine in conflict with Poland and Bolshevism, 1918-1923, p. 54
^ Volodymyr Kubiĭovych, Ukrainian National Association, 1963, Ukraine, a Concise Encyclopedia, Volume 1, p. 787
Spencer Tucker, Priscilla Mary Roberts, ABC-CLIO, 2005, World War I: A Student Encyclopedia, p. 361
Ivan Katchanovski, Zenon E. Kohut, Bohdan Y. Nebesio, Myroslav Yurkevich, Scarecrow Press, 2013, Historical Dictionary of Ukraine, p. 749
Keith Hitchins, Clarendon Press, 1994, Rumania 1866-1947, p. 279
^ Marcel Cornis-Pope, John Neubauer, John Benjamins Publishing, 2006, History of the Literary Cultures of East-Central Europe: Junctures and disjunctures in the 19th and 20th centuries, Volume 2, p. 58
Richard C. Hall, ABC-CLIO, 2014, War in the Balkans: An Encyclopedic History from the Fall of the Ottoman Empire to the Breakup of Yugoslavia, p. 50