**Table 2:** Fraction (in %) of positrons forming positronium in flight, in a completely neutral medium.
$\begin{table}\begin{displaymath}\begin{array}[b]{lccc} \hline \hline \mbox{Re... ... paper} & 95.5 & 89.6 & 81.7 \\ \hline \end{array}\end{displaymath}\end{table}$

	1 Introduction
	2 In-flight processes
	3 Processes after thermalization
	4 Annihilation spectra
	5 Summary and conclusions
	References