Man pages for variables
Variable Descriptions
| access | Accessor Functions |
| check | Check Observations Against Formal Description |
| factor_var | Unordered Categorical Variable |
| mkgrid | Generate Grids of Observations |
| numeric_var | Numeric Variable |
| ordered_var | Ordered Categorical Variable |
| variables-packages | General Information on the 'variables' Package |
| vars | Multiple Abstract Descriptions |
