Satco 90-1547 18W Two-Pin Bottom Screw Down G24D-2 and GX24D-2 Base - City Electric Supply
LH0888 Converts a G24d-2, GX24d-2 Socket to an E26/E27 Medium Base lamp Holder - Amazon.com
Osram 18w 2 pin GX24d-2 Warm White White 827 DULUX T / PLT Energy Saving CFL | eBay
E-Simpo G24d to E27 Adapter, 2P Light Socket Adapter, 21.8mm,G24 to E26/E27, GX24d to E27 Lamp Base Converter, Rohs.Need Bypass The Ballast! (60-Pack) - Amazon.com