diff --git a/factors.qmd b/factors.qmd
index c41ae4c..b1a98e0 100644
--- a/factors.qmd
+++ b/factors.qmd
@@ -425,6 +425,6 @@ In practice, `ordered()` factors behave very similarly to regular factors.
 There are only two places where you might notice different behavior:
 
 -   If you map an ordered factor to color or fill in ggplot2, it will default to `scale_color_viridis()`/`scale_fill_viridis()`, a color scale that implies a ranking.
--   If you use an ordered function in a linear model, it will use "polygonal contrasts". These are mildly useful, but you are unlikely to have heard of them unless you have a PhD in Statistics, and even then you probably don't routinely interpret them.
+-   If you use an ordered function in a linear model, it will use "polygonal contrasts". These are mildly useful, but you are unlikely to have heard of them unless you have a PhD in Statistics, and even then you probably don't routinely interpret them. If you want to learn more, I'd recommend `vignette("contrasts", package = "faux")` by Lisa DeBruine.
 
 Given the arguable utility of these differences, we don't generally recommend using ordered factors.