diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 8540dd3..5b7336a 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -11,6 +11,8 @@ jobs:
         run: sudo apt install fuse
       - name: Install pandoc
         uses: nikeee/setup-pandoc@v1
+      - name: Install pandoc-xnos
+        run: sudo apt install pandoc-xnos
       - name: Install pandoc-citeproc
         run: sudo apt-get -qq update && sudo apt-get install -y pandoc-citeproc && pandoc --version
       - name: Install tectonic
@@ -22,7 +24,7 @@ jobs:
       - name: Set up git repository
         uses: actions/checkout@v2
       - name: Convert with pandoc
-        run: mkdir log && mkdir output && pandoc --defaults pdf.yaml --to latex --metadata-file config.yaml --lua-filter .filters/abstract-to-meta.lua --template template/thesis.tex
+        run: mkdir log && mkdir output && pandoc --filter pandoc-xnos --defaults pdf.yaml --to latex --metadata-file config.yaml --lua-filter .filters/abstract-to-meta.lua --template template/thesis.tex --citeproc --csl https://www.zotero.org/styles/journal-of-the-acm --bibliography references.bib
       - name: Create release
         id: create_release
         uses: actions/create-release@v1
diff --git a/references.bib b/references.bib
index bd9aeff..07e89e4 100644
--- a/references.bib
+++ b/references.bib
@@ -348,3 +348,18 @@ @article{johnston2022
   with UAV warfare, which will add to my ethical discussion about UAVs for
   military use.}
 }
+@article{doukhi2022,
+  author={Doukhi, Oualid and Lee, Deok Jin},
+  journal={IEEE Access},
+  title={Deep Reinforcement Learning for Autonomous Map-Less Navigation of a Flying Robot},
+  year={2022},
+  volume={10},
+  number={},
+  pages={82964-82976},
+  doi={10.1109/ACCESS.2022.3162702},
+  annote={This article not only defines helpful mechanical equations used for
+    defining the quadcopter's mechanics, but it also describes their approach of
+  traning a quadcopter for navigation using a deep reinforcement learning
+  algorithm. They explain why they chose to not develop a path planning
+  algorithm, and I will explain their work in my review of related work.}
+}
diff --git a/thesis.md b/thesis.md
index 041de64..d86969d 100644
--- a/thesis.md
+++ b/thesis.md
@@ -261,6 +261,21 @@ In this project, the COEX Clover quadcopter is used.
 
 ## Theory
 
+With the earth's reference frame as $R^{E}$ and the quadcopter's body's
+reference frame as $R^{b}$, the *attitude* of the quadcopter is known by the
+orientation of $R^{b}$ with respect to $R^{E}$. We determine this from the
+rotational matrix defined in +@eq:rotationalmatrix [@doukhi2022].
+
+$$
+\begin{bmatrix}
+c \phi c \theta & s \phi s \theta c \psi - s \psi c \phi & c \phi s \theta c \psi + s \psi s \phi \\
+s \phi c \theta & s \phi s \theta s \psi + c \psi c \theta & c \phi s \theta s \psi - s \phi c \psi \\
+-s\theta & s \phi c \theta & c \phi c \theta
+\end{bmatrix}
+$$ {#eq:rotationalmatrix}
+
+<!-- FIXME: what is the Newton-Euler formulation? -->
+
 # Experiments
 
 ## Experimental Design