In "The Snows of Kilimanjaro," what literary elements does Hemingway use to indicate time periods?

The structure of the story is complex as Hemingway moves around in time. Primarily, it is divided between the events of the present, as Harry lays dying at the camp on the African plain with his wife trying to comfort him, and the events of the past which are relived in Harry's memory. The memory passages are distinguished by being printed in italics. Also, within the narrative of present events, Hemingway moves in and out of expository passages to introduce other facts from the past. Finally, he uses extended paragraph breaks, and in one case asterisks, to denote changes in time. (This use of graphics in structuring his stories occurs frequently in Hemingway's writing, one of the modern elements in his work.)

Also, to establish the specific time periods of Harry's memories, Hemingway uses a great many literary and historical allusions; he alludes primarily to the geographical settings and events in World War I and the 1920s.