• [2013-04-23] Cause of LED efficiency droop finally revealed
  in Tietoukka Monitor > 2013 > 2013-17 with light-emitting_diodes
• [2013-04-24] New LED streetlight design curbs light pollution
  + http://www.bbc.co.uk/news/technology-22292129 + http://www.opticsinfobase.org/oe/abstract.cfm?uri=oe-21-9-10612
  in Tietoukka Monitor > 2013 > 2013-17 with light-emitting_diodes light_pollution

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