4 Easy Ways to Change a Circular Fluorescent Light Bulb - wikiHow
Project 'Green' House #1: LED replacement lighting for circular fluorescent tubes // DavidJB.com // Python, Technology, Web, Linux, and more, by David Beitey
TCP Compact Fluorescent Circline Bulb - 30 Watt & 2850K Color Temperature - 4 Pin Base - Warm White - Ideal for Residential, Decorative, Indoor, Low & High Light Fixtures, Fluorescent & Neon Tubes - Amazon Canada