```
/**
* Calculate the critical buckling stress of a column according to the
* Load and Resistance Factor design method.
*
* @param yieldForce force at which the material will fail [Newtons]
* @pre > 0
* @param slenderness ratio of the column's length to a measure of its
* width (radius of gyration of its cross-section)
* [dimensionless] @pre > 0
*
* @returns the critical buckling stress as is used in the
* Load and Resistance Factor design method [Newtons]
*/
double criticalBucklingStress(double yieldForce, double slenderness);
```