+</pre>
+
+SDK reference documentation has additional, optional build requirements.
+
+h3. Java SDK documentation
+
+<pre>
+$ sudo apt install gradle
+</pre>
+
+h3. Python SDK documentation
+
+<pre>
+arvados/doc$ sudo apt install python3-venv
+arvados/doc$ python3 -m venv .venv
+arvados/doc$ .venv/bin/pip install pdoc setuptools
+</pre>
+
+Then you must activate the virtualenv (e.g., run @. .venv/bin/activate@) before you run the @bundle exec rake@ commands below.
+
+h3. R SDK documentation
+
+<pre>
+$ sudo apt install r-cran-devtools r-cran-roxygen2 r-cran-knitr r-cran-markdown r-cran-xml