diff --git a/NASA-TM/appendix.tex b/NASA-TM/appendix.tex
index 2078a00..7dd96cf 100644
--- a/NASA-TM/appendix.tex
+++ b/NASA-TM/appendix.tex
@@ -165,6 +165,7 @@ \subsection{Heat Exchanger Design} \label{app:heatX}
 Further calculations for the multipass heat exchanger can be found in the source code.
 
  \crefalias{section}{appsec}
+ \crefalias{subsection}{appsec}
 \Appendix{Sample Source Code and External Contributions} \label{app:2}  
 
 \subsection{Github}
@@ -204,4 +205,4 @@ \subsection{Usage Example}
 \inputminted[fontsize=\tiny]{python}{code/example4.py} %[linenos]
   %\end{adjustwidth} 
 
-\end{document}
\ No newline at end of file
+\end{document}
diff --git a/NASA-TM/build.sh b/NASA-TM/build.sh
index 6f9c2d4..9488f95 100644
--- a/NASA-TM/build.sh
+++ b/NASA-TM/build.sh
@@ -1,11 +1,18 @@
 #!/bin/bash
-#build pdf (with bibtex)
-"/usr/texbin/pdflatex" -synctex=1 -shell-escape -interaction=nonstopmode heading.tex
+set -e
+
+# Build the PDF with the TeX tools available on PATH.
+command -v pdflatex >/dev/null || {
+    echo "error: pdflatex is required and must be available on PATH" >&2
+    exit 1
+}
+
+pdflatex -synctex=1 -shell-escape -interaction=nonstopmode heading.tex
 bibtex heading.aux
-makeindex heading.nlo  -s nomencl.ist -o heading.nls
-"/usr/texbin/pdflatex" -synctex=1 -shell-escape -interaction=nonstopmode heading.tex
-"/usr/texbin/pdflatex" -synctex=1 -shell-escape -interaction=nonstopmode heading.tex
+makeindex heading.nlo -s nomencl.ist -o heading.nls
+pdflatex -synctex=1 -shell-escape -interaction=nonstopmode heading.tex
+pdflatex -synctex=1 -shell-escape -interaction=nonstopmode heading.tex
 
 mv heading.pdf hyperloop.pdf
 
-. clean.sh
+bash clean.sh
diff --git a/NASA-TM/heading.tex b/NASA-TM/heading.tex
index 80f8a1a..e56cebb 100644
--- a/NASA-TM/heading.tex
+++ b/NASA-TM/heading.tex
@@ -69,6 +69,7 @@
 
 %reference appendix
 \crefname{appsec}{Appendix}{Appendices}
+\Crefname{appsec}{Appendix}{Appendices}
 \begin{document}
 
 \setcounter{secnumdepth}{1}
@@ -85,4 +86,4 @@
 
 \subfile{appendix}
 
-\end{document}
\ No newline at end of file
+\end{document}