\( \boldsymbol{x}(u, v) = \sinh u \hskip 0.1em \begin{pmatrix} - a \sin v \\ b \cos v \\ \pm c \end{pmatrix} + \begin{pmatrix} a \cos v \\ b \sin v \\ 0 \end{pmatrix} \)
\( \left( - \dfrac{2 \pi}{3} \leq u \leq \dfrac{2 \pi}{3}, \, 0 \leq v \leq 2 \pi \right) \)