From the official NHLPA release:
16 PLAYERS ELECT SALARY ARBITRATION
TORONTO (July 5, 2012) – Sixteen players have elected Salary Arbitration:
David Perron (player has since signed a new contract)
The deadline for club-elected salary arbitration notification is July 6, 2012, at 5 p.m. ET. Hearings will be held in Toronto from July 20 to Aug. 4, 2012.