NAND and NOR are Functionally Complete/Historical Note

Historical Note on NAND and NOR are Functionally Complete
This result is specifically documented here because of its historical and scientific significance.

It was proved in $1913$ by, after whom the symbol $\uparrow$, the Sheffer stroke, is named after.

However, it later transpired that had noticed the same result in $1880$, but the paper in which this appeared was not published until $1933$.