diff --git a/simscape-nass.bib b/simscape-nass.bib
index e69de29..4628a6f 100644
--- a/simscape-nass.bib
+++ b/simscape-nass.bib
@@ -0,0 +1,28 @@
+@article{hauge04_sensor_contr_space_based_six,
+  author          = {G.S. Hauge and M.E. Campbell},
+  title           = {Sensors and Control of a Space-Based Six-Axis Vibration
+                  Isolation System},
+  journal         = {Journal of Sound and Vibration},
+  volume          = 269,
+  number          = {3-5},
+  pages           = {913-931},
+  year            = 2004,
+  doi             = {10.1016/s0022-460x(03)00206-2},
+  url             = {https://doi.org/10.1016/s0022-460x(03)00206-2},
+  keywords        = {parallel robot, favorite},
+}
+
+
+
+@article{preumont08_trans_zeros_struc_contr_with,
+  author          = {Preumont, Andr{\'e} and De Marneffe, Bruno and Krenk,
+                  Steen},
+  title           = {Transmission Zeros in Structural Control With Collocated
+                  Multi-Input/multi-Output Pairs},
+  journal         = {Journal of guidance, control, and dynamics},
+  volume          = 31,
+  number          = 2,
+  pages           = {428--432},
+  year            = 2008,
+}
+
diff --git a/simscape-nass.pdf b/simscape-nass.pdf
index 1694d66..8732d73 100644
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