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diff --git a/01.courses/01.optics/03.the-nature-of-light/02.cheatsheet/frontmatter.yaml b/01.courses/01.optics/03.the-nature-of-light/02.cheatsheet/frontmatter.yaml
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diff --git a/01.courses/01.optics/03.the-nature-of-light/03.annex/annex.fr.md b/01.courses/01.optics/03.the-nature-of-light/03.annex/annex.fr.md
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 ---
 
+Voir [Constante](#une-constante-fondamentale-de-la-nature-la-vitesse-de-la-lumière)
 
 ## Annexe
 
diff --git a/01.courses/01.optics/03.the-nature-of-light/03.annex/frontmatter.yaml b/01.courses/01.optics/03.the-nature-of-light/03.annex/frontmatter.yaml
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