Relation between Signed and Unsigned Stirling Numbers of the First Kind

Theorem
Let $m, n \in \Z_{\ge 0}$ be positive integers.

Then:
 * $\displaystyle \left[{n \atop m}\right] = \left({-1}\right)^{n + m} s \left({n, m}\right)$

where:
 * $\displaystyle \left[{n \atop m}\right]$ denotes an unsigned Stirling number of the first kind
 * $s \left({n, m}\right)$ denotes a signed Stirling number of the first kind.