Update citations.

Author: dpad

CITATION.bib

@@ -1,6 +1,18 @@
+@mastersthesis{Padilha2021,
+  doi = {10.13140/RG.2.2.14175.79525},
+  url = {http://rgdoi.net/10.13140/RG.2.2.14175.79525},
+  author = {Padilha, Dan},
+  language = {en},
+  title = {Composable Astrodynamics Software via Multiple Dispatch and Meta-Programming},
+  school = {The University of Tokyo},
+  year = {2021},
+  month = aug
+}
+
 @inproceedings{OrbitalTrajectories,
   url = {https://www.researchgate.net/publication/348929030_Modern_Numerical_Programming_with_Julia_for_Astrodynamic_Trajectory_Design},
   year = {2021},
+  month = feb,
   publisher = {AAS/AIAA},
   author = {Padilha, Dan and Dei Tos, Diogene Alessandro and Baresi, Nicola and Kawaguchi, Junichiro},
   title = {Modern Numerical Programming with Julia for Astrodynamic Trajectory Design},

README.md

@@ -2,7 +2,7 @@
 
 | **Documentation**   |  **Tests**     |  Citation| License
 |:--------:|:----------------------:|:-----:|:-----:|
-|[![](https://img.shields.io/badge/docs-online-blue.svg)](https://dpad.github.io/OrbitalTrajectories.jl/stable/)| [![CI](https://github.com/dpad/OrbitalTrajectories.jl/workflows/CI/badge.svg)](https://github.com/dpad/OrbitalTrajectories.jl/actions) [![codecov](https://codecov.io/gh/dpad/OrbitalTrajectories.jl/branch/master/graph/badge.svg)](https://codecov.io/gh/dpad/OrbitalTrajectories.jl) | [![reference](https://img.shields.io/badge/Thesis%20%28v0.2.0dev%29-Padilha%202021-brightgreen)](https://www.researchgate.net/publication/353906343_Composable_Astrodynamics_Software_via_Multiple_Dispatch_and_Meta-Programming) [![reference](https://img.shields.io/badge/Paper%20%28v0.1.1%29-Padilha%20et%20al%202021-brightgreen)](https://dpadilha.com/Padilha%20-%20AAS%2021-303.pdf) | [![GitHub license](https://img.shields.io/github/license/dpad/OrbitalTrajectories.jl)](LICENSE)
+|[![](https://img.shields.io/badge/docs-online-blue.svg)](https://dpad.github.io/OrbitalTrajectories.jl/stable/)| [![CI](https://github.com/dpad/OrbitalTrajectories.jl/workflows/CI/badge.svg)](https://github.com/dpad/OrbitalTrajectories.jl/actions) [![codecov](https://codecov.io/gh/dpad/OrbitalTrajectories.jl/branch/master/graph/badge.svg)](https://codecov.io/gh/dpad/OrbitalTrajectories.jl) | [![reference](https://img.shields.io/badge/Thesis%20%28as%20of%20v0.2.0dev%29-Padilha%202021-brightgreen)](https://www.researchgate.net/publication/353906343_Composable_Astrodynamics_Software_via_Multiple_Dispatch_and_Meta-Programming) [![reference](https://img.shields.io/badge/Paper%20%28as%20of%20v0.1.1%29-Padilha%20et%20al%202021-brightgreen)](https://dpadilha.com/Padilha%20-%20AAS%2021-303.pdf) | [![GitHub license](https://img.shields.io/github/license/dpad/OrbitalTrajectories.jl)](LICENSE)
 
 *OrbitalTrajectories.jl is a modern orbital trajectory design, optimisation, and analysis library for Julia, providing methods and tools for designing spacecraft orbits and transfers via high-performance simulations of astrodynamical models.*
 
@@ -25,8 +25,19 @@ Distributed under the [Apache License 2.0](LICENSE)
 
 Copyright 2021 Dan Padilha ([dpadilha.com](http://www.dpadilha.com))
 
-If you use OrbitalTrajectories.jl in a scientific project that leads to a publication, we'd appreciate you citing our paper as follows:
+If you use OrbitalTrajectories.jl in a scientific project that leads to a publication, we'd appreciate you citing our work as follows:
 ```
+@mastersthesis{Padilha2021,
+  doi = {10.13140/RG.2.2.14175.79525},
+  url = {http://rgdoi.net/10.13140/RG.2.2.14175.79525},
+  author = {Padilha, Dan},
+  language = {en},
+  title = {Composable Astrodynamics Software via Multiple Dispatch and Meta-Programming},
+  school = {The University of Tokyo},
+  year = {2021},
+  month = aug
+}
+
 @inproceedings{OrbitalTrajectories,
   url = {https://www.researchgate.net/publication/348929030_Modern_Numerical_Programming_with_Julia_for_Astrodynamic_Trajectory_Design},
   year = {2021},