https://www.edutopia.org/envision-schools-rigor/
The Four R's: Rigor in Twenty-First-Century Schools | Edutopia
Envision Schools embraces four principles for preparing students for success in college and careers, including rigor.
twenty first century schoolsthe fourrigor
https://www.gov.wales/oral-statement-twenty-first-century-schools
Oral Statement - Twenty-first Century Schools (17 January 2012) | GOV.WALES
Leighton Andrews, Minister for Education and Skills
twenty first century schools17 januaryoralstatement