These 20 columns probably refer to Mesoamerican calendars, that have equal number of days.

In architecture, "column" refers to such a structural element that also has certain proportional and decorative features.

Fifth column refers to a group of people who undermine a larger group from within.

The column did not refer to any scientific studies.

The second column refers to the episode's number in that particular season.

The column refers to the struggle and the revival of the Armenian nation.

This column refers only to the judges' terms in the Commerce Court.

The first column refers to the episode's number in the overall series.

This column referred erroneously on Monday to South's prospects in the deal shown.

The column also referred incorrectly to the Olympics Games scheduled for 1996.