Columbia subject headings:
Russia (Federation)--Foreign relations--Ukraine.
Ukraine--Foreign relations--Russia (Federation)
Harvard subject headings:
Russia (Federation)--Foreign relations--Ukraine.
Ukraine--Foreign relations--Russia (Federation)
Princeton subject headings:
Crimea (Ukraine)--Politics and government--Sources.
Russia (Federation)--Foreign relations--Ukraine--Sources.
Russia (Federation). Voenno-Morskoĭ Flot. Chernomorskiĭ flot--Sources.
Ukraine--Foreign relations--Russia (Federation)--Sources.
Ukraine. Voenno-Morskie Sily. Chernomorskiĭ flot--Sources.