diff --git a/authesis.cls b/authesis.cls
index cdbedcb..4299c43 100644
--- a/authesis.cls
+++ b/authesis.cls
@@ -28,6 +28,8 @@
 
 \LoadClass[letterpaper,12pt,oneside]{report}
 
+\RequirePackage{xkeyval}
+
 \RequirePackage[english]{babel}
 \RequirePackage{geometry}
 \RequirePackage{setspace}
@@ -37,16 +39,21 @@
 % Dissertation (default) or thesis
 \newif\ifdissertation
 \dissertationtrue
-\DeclareOption{thesis}{\dissertationfalse}
+\DeclareOptionX{thesis}{\dissertationfalse}
 % Whether to print copyright notice
 \newif\ifcopyright
 \copyrighttrue
-\DeclareOption{nocopyright}{\copyrightfalse}
+\DeclareOptionX{nocopyright}{\copyrightfalse}
 % Whether to make the text ragged
 \newif\ifragged
 \raggedfalse
-\DeclareOption{ragged}{\raggedtrue}
-\ProcessOptions\relax
+\DeclareOptionX{ragged}{\raggedtrue}
+% Bibliography style
+\PassOptionsToPackage{style=phys}{biblatex}
+\DeclareOptionX{bibstyle}[phys]{
+    \PassOptionsToPackage{style=#1}{biblatex}
+}
+\ProcessOptionsX\relax
 
 % Default formatting
 \newgeometry{margin=1in}
@@ -232,3 +239,9 @@
 \renewcommand*{\l@section}{\@dottedtocline{1}{1.5em}{2.5em}}
 \renewcommand*{\l@figure}{\@dottedtocline{0}{0em}{2.5em}}
 \renewcommand*{\l@table}{\@dottedtocline{0}{0em}{2.5em}}
+
+% bibliography
+\RequirePackage[backend=biber, biblabel=brackets, defernumbers=true]{biblatex}
+\DeclareCiteCommand{\citenum}{}{\bibhyperref{\printfield{labelnumber}}}{\multicitedelim}{}
+\setlength{\bibitemsep}{\baselineskip}
+\AtBeginBibliography{\singlespacing}
\ No newline at end of file
diff --git a/main.tex b/main.tex
index dec92b2..ea4375d 100644
--- a/main.tex
+++ b/main.tex
@@ -13,6 +13,7 @@
 % * thesis: Master's thesis rather than dissertation
 % * nocopyright: Disable copyright notice
 % * ragged: Use ragged right edge rather than justified text (better for accessibility)
+% * bibstyle: biblatex bibliography style
 \documentclass{authesis}
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -30,11 +31,12 @@
 %  \includegraphics[alt={Alt text...}]{image.png}
 \usepackage{graphicx}
 
-% Bibliography. biber must be set as the backend, style can be changed.
+% Bibliography (uses biblatex with biber as backend)
+% Set the bibliography style using the bibstyle option of the class.
+% Most other options can be changed here using
+% \ExecuteBibliographyOptions{}
 \usepackage[hidelinks,pdfusetitle]{hyperref}
 \urlstyle{same}
-\usepackage[backend=biber,style=phys,biblabel=brackets,defernumbers=true]{biblatex}
-\DeclareCiteCommand{\citenum}{}{\bibhyperref{\printfield{labelnumber}}}{\multicitedelim}{}
 \addbibresource{./references.bib}
 
 % Footnotes