NCSS, 2013 [Sursă]

College, Career & Civic Life (C3) Framework for Social Studies State Standards
National Council for the Social Studies. (2013). The college, career, and civic life (C3) framework for social studies state standards: Guidance for enhancing the rigor of K–12 civics, economics, geography, and history. Silver Spring, MD: Author. https://www.socialstudies.org/system/files/c3/C3-Framework-for-Social-Studies.pdf