Experimental work
\cite{Echenique_1981}
\cite{Puska_1983}
\cite{Echenique_1986}
\cite{BLUME_1980}
\cite{Vald_s_1994}
\cite{Figueroa_2007}
\cite{Markin_2008}
\cite{Cantero_2009}
\cite{Goebl_2013}
\cite{Roth_2017}
\cite{Roth_2017a}
added Cayzac not sure if it's necessary though
\cite{Cayzac_2017}
Theoretical work
\cite{Zeb_2012}