diff --git a/notebooks/chapter_4_pixelizations/tutorial_1_pixelizations.ipynb b/notebooks/chapter_4_pixelizations/tutorial_1_pixelizations.ipynb
index 521f8be..0c4dbc0 100644
--- a/notebooks/chapter_4_pixelizations/tutorial_1_pixelizations.ipynb
+++ b/notebooks/chapter_4_pixelizations/tutorial_1_pixelizations.ipynb
@@ -117,8 +117,14 @@
     "Next, lets set up a `Mesh` using the `mesh` module. The mesh represents the pixel-grid used by the pixelization\n",
     "to reconstruct the galaxy.\n",
     "\n",
-    "There are multiple `Mesh`'s available. For now, we'll keep it simple and use a uniform \n",
-    "rectangular grid, whose `shape` defines its $(y,x)$ dimensions."
+    "There are multiple `Mesh`'s available. For now, we'll keep it simple and use a rectangular\n",
+    "grid, whose `shape` defines its $(y,x)$ dimensions.\n",
+    "\n",
+    "The `RectangularAdaptDensity` mesh adapts its pixels to the density of the traced source-plane\n",
+    "grid via the ray-guided transformed uniform (RTU) grid formulation of Enzi et al. (2026)\n",
+    "(https://arxiv.org/abs/2606.30620), which should be cited in published work using this mesh.\n",
+    "Note that whereas that paper pairs the RTU grid with a Gaussian-process source prior,\n",
+    "**PyAutoLens** instead uses its own regularization schemes, introduced later in this chapter."
    ]
   },
   {
diff --git a/scripts/chapter_4_pixelizations/tutorial_1_pixelizations.py b/scripts/chapter_4_pixelizations/tutorial_1_pixelizations.py
index fbad604..230863a 100644
--- a/scripts/chapter_4_pixelizations/tutorial_1_pixelizations.py
+++ b/scripts/chapter_4_pixelizations/tutorial_1_pixelizations.py
@@ -54,8 +54,14 @@
 Next, lets set up a `Mesh` using the `mesh` module. The mesh represents the pixel-grid used by the pixelization
 to reconstruct the galaxy.
 
-There are multiple `Mesh`'s available. For now, we'll keep it simple and use a uniform 
-rectangular grid, whose `shape` defines its $(y,x)$ dimensions.
+There are multiple `Mesh`'s available. For now, we'll keep it simple and use a rectangular
+grid, whose `shape` defines its $(y,x)$ dimensions.
+
+The `RectangularAdaptDensity` mesh adapts its pixels to the density of the traced source-plane
+grid via the ray-guided transformed uniform (RTU) grid formulation of Enzi et al. (2026)
+(https://arxiv.org/abs/2606.30620), which should be cited in published work using this mesh.
+Note that whereas that paper pairs the RTU grid with a Gaussian-process source prior,
+**PyAutoLens** instead uses its own regularization schemes, introduced later in this chapter.
 """
 mesh = al.mesh.RectangularAdaptDensity(shape=(25, 25))