Update README.md

Author: tipf

README.md

@@ -17,6 +17,8 @@ This library is the implementation of [1] and [2]. Further references will be ad
 
 [1] Tim Pfeifer and Peter Protzel, Expectation-Maximization for Adaptive Mixture Models in Graph Optimization, Proc. of Intl. Conf. on Robotics and Automation (ICRA), 2019
 
+[2] Tim Pfeifer and Peter Protzel, Incrementally learned Mixture Models for GNSS Localization, Proc. of Intelligent Vehicles Symposium (IV), 2019
+
 BibTeX:
 
         @InProceedings{Pfeifer2019,
@@ -26,10 +28,6 @@ BibTeX:
         year      = {2019},
         }
 
-[2] Tim Pfeifer and Peter Protzel, Incrementally learned Mixture Models for GNSS Localization, Proc. of Intelligent Vehicles Symposium (IV), 2019
-
-BibTeX:
-
         @InProceedings{Pfeifer2019a,
         author    = {Tim Pfeifer and Peter Protzel},
         title     = {Incrementally learned Mixture Models for GNSS Localization},