3. Dates

• 1950s, '60s, and '70s [reverse apostrophe]
• CE is implied unless it is used in proximity to a date BCE. BCE is always marked unless all dates in the text are BCE. There is always a space between the number and BCE or CE, BCE and CE always appear after the number, and there are never periods separating the numbers (e.g., 354 BCE–22 CE; 354–12 BCE; 258–508; 1956–1990).