remove empty bibliography

content/zettels/active_damping.md

@@ -17,6 +17,3 @@ There are two main control architecture to actively damp structures:
 The idea is to apply a force proportional to the velocity (either relative or inertial) of the structure.
 
 These are usually applied in a collocated way, meaning that the actuator and sensors are collocated (fixed to the same DoF), in order to have guaranteed stability.
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-## Bibliography {#bibliography}