additional citations

README.md

@@ -96,7 +96,4 @@ Please see the [`examples/`](examples) directory and the [`USAGE`](USAGE.md) fil
 
 GTSAM was developed in the lab of [Frank Dellaert](http://www.cc.gatech.edu/~dellaert) at the [Georgia Institute of Technology](http://www.gatech.edu), with the help of many contributors over the years, see [THANKS](THANKS.md).
 
-## GTSAM Citation
-
-Use the following to cite GTSAM:
 

references.bib

@@ -1,9 +1,24 @@
 @misc{gtsam,
-    author       = {Borg Lab},
+    author       = {{Borg Lab}},
     title        = {{GTSAM}},
     month        = jul,
     year         = 2020,
-    doi          = {},
     version      = {4.0.3},
-    url          = {}
-    }
+    url          = {https://github.com/borglab/gtsam}
+    }
+
+@article{imu-preintegration,
+    author = {{Christian Forster and Luca Carlone and Frank Dellaert and Davide Scaramuzza}},
+    title = {{IMU preintegration on Manifold for Efficient Visual-Inertial Maximum-a-Posteriori Estimation}},
+    year = 2015
+
+}
+
+@techreport{factorgraphs,
+    author = {Frank Dellaert},
+    title = {{Factor Graphs and GTSAM: A Hands-On Introduction}},
+    number = {GT-RIM-CP\&R-2012-002},
+    month = jul,
+    year = 2012
+
+}