\documentclass[de]{ptb-declaration}

\missingEntries{ 0 }

\myref{7.5-1V-15-05}
\mymail{2018-10-08}
\myfax{+49-30-3481-7490}
\myemail{vacuum.cal@ptb.de }
\yourref{Wrdlbrmpft0815} 

\begin{document}
\end{document}