diff --git a/org/bibliography.org b/org/bibliography.org
index ed42996..c743941 100644
--- a/org/bibliography.org
+++ b/org/bibliography.org
@@ -38,6 +38,15 @@
 #+PROPERTY: header-args:latex+ :post pdf2svg(file=*this*, ext="png")
 :END:
 
+Things to add:
+- cite:zheng20_multi_frequen_mimo_contr_method
+- cite:ting05_error
+- cite:rahman98_multiax
+- cite:rahman96_six
+- cite:beijen18_exper_estim_trans_matric_indus
+- cite:xie17_model_contr_hybrid_passiv_activ
+- cite:chi15_desig_exper_study_vcm_based
+
 * Books
 |                                                        | <c>  |
 | Link to bibliography                                   | Read |
diff --git a/org/ref.bib b/org/ref.bib
index 06ed2a7..2168586 100644
--- a/org/ref.bib
+++ b/org/ref.bib
@@ -1232,3 +1232,101 @@
   url             = {https://doi.org/10.1088/0964-1726/13/4/025},
   tags            = {parallel robot},
 }
+
+@article{chi15_desig_exper_study_vcm_based,
+  author          = {Weichao Chi and Dengqing Cao and Dongwei Wang and Jie Tang
+                  and Yifan Nie and Wenhu Huang},
+  title           = {Design and Experimental Study of a Vcm-Based Stewart
+                  Parallel Mechanism Used for Active Vibration Isolation},
+  journal         = {Energies},
+  volume          = 8,
+  number          = 8,
+  pages           = {8001-8019},
+  year            = 2015,
+  doi             = {10.3390/en8088001},
+  url             = {https://doi.org/10.3390/en8088001},
+  tags            = {parallel robot},
+}
+
+@inproceedings{xie17_model_contr_hybrid_passiv_activ,
+  author          = {Xie, Xiling and Wang, Chaoxin and Zhang, Zhiyi},
+  title           = {Modeling and Control of A Hybrid Passive/Active Stewart
+                  Vibration Isolation Platform},
+  booktitle       = {INTER-NOISE and NOISE-CON Congress and Conference
+                  Proceedings},
+  year            = 2017,
+  volume          = 255,
+  number          = 6,
+  pages           = {1844--1853},
+  organization    = {Institute of Noise Control Engineering},
+  tags            = {parallel robot},
+}
+
+@article{beijen18_exper_estim_trans_matric_indus,
+  author          = {Michiel A. Beijen and Robbert Voorhoeve and Marcel F.
+                  Heertjes and Tom Oomen},
+  title           = {Experimental Estimation of Transmissibility Matrices for
+                  Industrial Multi-Axis Vibration Isolation Systems},
+  journal         = {Mechanical Systems and Signal Processing},
+  volume          = 107,
+  number          = {nil},
+  pages           = {469-483},
+  year            = 2018,
+  doi             = {10.1016/j.ymssp.2018.01.013},
+  url             = {https://doi.org/10.1016/j.ymssp.2018.01.013},
+  tags            = {parallel robot},
+}
+
+@inproceedings{rahman96_six,
+  author          = {Zahidul Rahman and John Spanos},
+  title           = {Six axis vibration isolation, suppression and steering
+                  system for space applications},
+  booktitle       = {Dynamics Specialists Conference},
+  year            = 1996,
+  pages           = {nil},
+  doi             = {10.2514/6.1996-1211},
+  url             = {https://doi.org/10.2514/6.1996-1211},
+  month           = 4,
+  tags            = {parallel robot},
+}
+
+@inproceedings{rahman98_multiax,
+  author          = {Zahidul H. Rahman and John T. Spanos and Robert A. Laskin},
+  title           = {Multiaxis vibration isolation, suppression, and steering
+                  system for space observational applications},
+  booktitle       = {Telescope Control Systems III},
+  year            = 1998,
+  pages           = {nil},
+  doi             = {10.1117/12.308821},
+  url             = {https://doi.org/10.1117/12.308821},
+  month           = 5,
+  tags            = {parallel robot},
+}
+
+@inproceedings{ting05_error,
+  author          = {Yung Ting and Ho-Chin Jar and Chun-Chung Li},
+  title           = {Error compensation and feedforward controller design for a
+                  6-dof micro-positioning platform},
+  booktitle       = {2005 IEEE/RSJ International Conference on Intelligent
+                  Robots and Systems},
+  year            = 2005,
+  pages           = {nil},
+  doi             = {10.1109/iros.2005.1545073},
+  url             = {https://doi.org/10.1109/iros.2005.1545073},
+  month           = {-},
+  tags            = {parallel robot},
+}
+
+@article{zheng20_multi_frequen_mimo_contr_method,
+  author          = {Yan Zheng and Zhicheng Zhou and Hai Huang},
+  title           = {A Multi-Frequency Mimo Control Method for the 6dof
+                  Micro-Vibration Exciting System},
+  journal         = {Acta Astronautica},
+  volume          = 170,
+  number          = {nil},
+  pages           = {552-569},
+  year            = 2020,
+  doi             = {10.1016/j.actaastro.2020.02.033},
+  url             = {https://doi.org/10.1016/j.actaastro.2020.02.033},
+  tags            = {parallel robot},
+}