%&LaTeX
\documentclass{article}

\usepackage{soul}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{textcomp}

\begin{document}

\begin{thebibliography}{5}

\bibitem{Trifonov_etal2016} Trifonov A, Tong C-YE, Lobanov Y, Kaurova N, Blundell R, Goltsman G. Gap frequency and photon absorption in a hot electron bolometer. In: Proc. 27$^{th}$ Int. Symp. Space Terahertz Technol.; 2016. 121.

\end{thebibliography}

\end{document}

