(b) References to dates
17) Write out the month, preceded by a figure for the day. Use four digits when referring to specific years.
For example:
15 March 1928
The format March 15, 1928 is practice in the U.S. only. Never write a date according to any of the following structures:
…the 15th day of March 1928 (written out)
the fifteenth day of March 1928 (even worse)
15th March 1928 (ordinal day indication)
March 15 1928 (without comma)
March 15th, 1928 (combination ordinal indication and reverse order)
09 March 1928 (zero for days below 10)
Avoid an all-figure style of writing dates. Example: not 15-3-1928, and 1966 not ’66
18) When referring to decades write the 1980s (without apostrophe).