1. http://www.kantei.go.jp/jp/singi/ondanka/kaisai/080729/honbun.pdf
2. http://www.enecho.meti.go.jp/category/electricity_and_gas/electric/summary/regulations/pdf/keito_guideline.pdf
3. http://www.meti.go.jp/policy/tech_evaluation/e00/03/h22/391.pdf
4. Oozeki T. Review of PV output forecast technologies 2014 http://ogimotolab.iis.u-tokyo.ac.jp/html/workshop/20140325/20140325.4.pdf
5. Validation of short and medium term operational solar radiation forecasts in the US;Perez;Solar Energy,2010