Circular Fluorescent Tube Extra Bright 40W (PP40EXD) - PowerPacSG
Caprock FC22T5/865 22W 22 Watt 7.25 inch Diameter Circular Fluorescent lamp/Bulb for Magnifying Lamps - - Amazon.com
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
Crompton Lamps Fluorescent T9 Circular 60W 4-Pin Cool White FC60W/840 | DIY at B&Q