Part of that strategy was the expulsion of Serbs from Croatia and from one part of BiH, the seizure of Kosovo and Metohija, the separation of Montenegro by illegal referendum, and finally the assimilation of the remaining Serb population through political engineering.
Summary
Crimea became part of Russia in March 2014 by a referendum held after the coup in Kiev. 96.77 percent of the voters of the Republic of Crimea and 95.6 percent of the residents of Sevastopol voted in favor of unification with Russia.
Disproof
This is a recurring pro-Kremlin disinformation narrative on Russia's annexation of Crimea, claiming that people chose to rejoin Russia through a legal and democratic referendum. For similar cases, see here and here. No international body recognises the so-called referendum held on 16th of March 2014. On the 27th of February 2014, when it was announced, the UN General Assembly adopted a resolution which stated that the referendum in Crimea was not valid and could not serve as a basis for any change in the status of the peninsula. A year after the illegal annexation, even the Kremlin admitted that the plan to annex Crimea was ordered weeks before the so-called referendum.
It is also a recurring pro-Kremlin disinformation narrative about the Euromaidan claiming that there was a coup d’état. There was no coup d’état in Ukraine. The onset of the Euromaidan protests was a spontaneous and endogenous reaction by numerous segments of the Ukrainian population to former President Yanukovych’s sudden withdrawal from the promised Association Agreement with the European Union in November 2013. See the full debunk here