Wadler’s influential “monads” paper for Haskell. It seems like a classic case of making something simple sound profound and mysterious. And companion paper by Hughes on “why functional programming matters” . See also some comments above.
McCarthy’s original LISP paper. Just terrible. He made a serious error picking Lambda calculus as a base notation.
A problem FSMLabs detected with GPS on London LD4 datacenter has been fixed.
Dennis Ritchie and Albert Meyer on classification of recursive functions. I wish I could find a full copy of this.
The SEC Consolidated Audit is pushing clock sync requirements, but needs improvement.
The most successful functional language – Mathematica.
A critique of Haskell
A Haskell project at Facebook.
Some real engineering: the gcc optimizers.
Categories as algebra: An essential ingredient in the theory of monoids (via @joelvanderwerf )