{
  "accessedAt": "2026-11-01",
  "sources": [
    {
      "url": "https://thomas.math.gatech.edu/FC/fourcolor.html",
      "title": "The Four Color Theorem \u2014 Robertson, Sanders, Seymour and Thomas",
      "usedFor": "Established theorem and boundary-segment versus point convention; not the source of our worksheet drawings."
    },
    {
      "url": "https://nrich.maths.org/articles/four-colour-theorem",
      "title": "NRICH \u2014 The Four Colour Theorem",
      "usedFor": "Map/graph duality and mathematical context."
    },
    {
      "url": "https://mathequalslove.net/four-color-theorem-activity/",
      "title": "Sarah Carter \u2014 Four Color Theorem Activity",
      "usedFor": "Observed classroom need for simple maps before harder ones; no images or worksheet designs copied."
    }
  ]
}