The given date was a Monday.
May 18, 1981 was a Monday.
December 18, 1981 was a Friday.
February 18, 1981 was a Wednesday.
November 18, 1981 fell on a Wednesday.
It was a Sunday
August 18th, 1981 fell on a Tuesday.
It was a Friday.
It was a Sunday.
May 16 1981 was a Saturday.
21st May 1981, was a Thursday.
23rd May 1981, was a Saturday.
May 25, 1981 was a Monday.