[Outline map of Eastern Europe showing exisiting and proposed frontiers.]
MLA
[Outline Map of Eastern Europe Showing Exisiting and Proposed Frontiers.]. s.n., 191AD. https://collections.library.yale.edu/catalog/15238035.
APA, 6th edition
[Outline map of Eastern Europe showing exisiting and proposed frontiers.]. (191 C.E.). [Maps, Outline maps]. s.n., https://collections.library.yale.edu/catalog/15238035.