Bulbmaster FC12T9/CW 32 Watts 12 Inch Round T9 Fluorescent Circular Light Bulb, Cool White 4100K, FC12T9 1930 Lumens G10Q 4-Pin Base 32W Circline Ceiling Lights - Amazon.com
Project 'Green' House #1: LED replacement lighting for circular fluorescent tubes // DavidJB.com // Python, Technology, Web, Linux, and more, by David Beitey
4 Easy Ways to Change a Circular Fluorescent Light Bulb - wikiHow
AMATRON ETL Listed 16" T9 24W LED Circline Bulb LED Circular Tube 5000K Daylight Frosted Lens with Non-Dimmable External Power Driver to Replace 16 inch 40W Fluorescent Circline - Led Household Light