diff --git a/src/apt-packages/NOTES.md b/src/apt-packages/NOTES.md
index c45a00a..441e483 100644
--- a/src/apt-packages/NOTES.md
+++ b/src/apt-packages/NOTES.md
@@ -31,4 +31,4 @@ The following example installs the `r-cran-curl` package after the `r-apt` Featu
 "overrideFeatureInstallOrder": [
     "ghcr.io/rocker-org/devcontainer-features/r-apt"
 ]
-```
+```
\ No newline at end of file
diff --git a/src/r-apt/NOTES.md b/src/r-apt/NOTES.md
index 190cb25..d9d8024 100644
--- a/src/r-apt/NOTES.md
+++ b/src/r-apt/NOTES.md
@@ -29,7 +29,7 @@ apt-get -y install --no-install-recommends r-cran-dplyr
 Thanks to [r2u](https://eddelbuettel.github.io/r2u/), on Ubuntu,
 all packages on CRAN and BioConductor can be installed via apt.
 
-If you want to install R packages via apt during the container build phase,
+If you want to install R packages via apt during the container build phase (as opposed to installing R packages using the [`r-packages` Feature](https://github.com/rocker-org/devcontainer-features/tree/main/src/r-packages)),
 you can use [the `ghcr.io/rocker-org/devcontainer-features/apt-packages` Feature](https://github.com/rocker-org/devcontainer-features/blob/main/src/apt-packages)
 to do so.
 
@@ -48,6 +48,20 @@ to do so.
 `ghcr.io/rocker-org/devcontainer-features/apt-packages` is not guaranteed to install after this Feature,
 so be sure to set up [the `overrideFeatureInstallOrder` property](https://containers.dev/implementors/features/#overrideFeatureInstallOrder).
 
+When installing R packages via `r-cran-<package>` using the `apt-packages` Feature, R package name references must be lowercase. For example, the following snippet installs the {kableExtra} R package.
+
+```json
+"features": {
+    "ghcr.io/rocker-org/devcontainer-features/r-apt:latest": {},
+    "ghcr.io/rocker-org/devcontainer-features/apt-packages:1": {
+        "packages": "r-cran-kableextra"
+    }
+},
+"overrideFeatureInstallOrder": [
+    "ghcr.io/rocker-org/devcontainer-features/r-apt"
+]
+```
+
 ### Source installation via R
 
 Packages that cannot be installed via apt must be installed using the R functions.