diff --git a/content/zettels/tuned_mass_damper.md b/content/zettels/tuned_mass_damper.md
index bffed15..4c299da 100644
--- a/content/zettels/tuned_mass_damper.md
+++ b/content/zettels/tuned_mass_damper.md
@@ -117,3 +117,9 @@ This relation can help to determine the minimum mass of the TMD that will give a
 ## Manufacturers {#manufacturers}
 
 <https://vibratec.se/en/product/high-frequency-tuned-mass-damper/>
+
+## References
+
+<style>.csl-entry{text-indent: -1.5em; margin-left: 1.5em;}</style><div class="csl-bib-body">
+  <div class="csl-entry"><a id="citeproc_bib_item_1"></a>Elias, Said, and Vasant Matsagar. 2017. “Research Developments in Vibration Control of Structures Using Passive Tuned Mass Dampers.” <i>Annual Reviews in Control</i> 44 (nil): 129–56. doi:<a href="https://doi.org/10.1016/j.arcontrol.2017.09.015">10.1016/j.arcontrol.2017.09.015</a>.</div>
+</div>