Making text smaller in one block in tikzposter

Question

I am trying to make an a1 academic poster in tikzposter and need to use 3 references, which I have put into a block using bibtex.

Is there a way to make the font in the block I have put references in smaller than in the other blocks? I have used size 20pt font, which I don't want to make any smaller for the content otherwise it will be hard to read but I'm running out of space and so could do with any extra I can get!

Here is the basic code I am using, I want to make the font size in the box called References smaller:

\documentclass[20pt,a1paper, landscape,colspace=0.7cm,blockverticalspace=1cm]{tikzposter}
\usepackage{graphicx}
\usepackage{amsmath}
\usepackage{multicol}
\usepackage{adjustbox}
\usepackage{capt-of}

\setlength{\columnsep}{1.5cm}

\useblockstyle{Basic}

\usecolorstyle{Sweden}
\tikzposterlatexaffectionproofoff

\title{\parbox{0.5\linewidth}{title}}
\author{author}
\institute{institution}

\begin{document}

% Introduction.
\maketitle

\begin{columns}

\column{0.7}
\block{Introduction}
{\begin{multicols}{2}
blah blah blah
\end{multicols}
}    

\begin{subcolumns}
\subcolumn{0.5}
\block{test}
{test
}

\subcolumn{0.5}
\block{test}
{testtest}

\end{subcolumns}

\column{0.3}
\block{}
{\vspace{-2cm}
\begin{tikzfigure}[caption]
\includegraphics[width=0.25\textwidth]{diagram.png}
\end{tikzfigure}
}


\block{References}
{\begingroup
\renewcommand\refname{\vskip -2cm}
\bibliographystyle{abbrv}
\bibliography{references}
\endgroup
}


\end{columns}

\end{document}

Answer 1

Putting \small at the beggining of the block works for me.

\block{References}
{
  \small
  \blindtext
}