\item$f, F, A$ can be implemented as \texttt{(*)AbstractFunction$\langle$ReturnType, InputType1, InputType2, ...$\rangle$}, where \texttt{(*)}$\in$\{$\emptyset$, \texttt{Binary}, \texttt{Tertiary}, \texttt{Quart}\} depending on the number of input arguments.
\item The data-structure \texttt{DOFVector<*>} is always a pointer to a DOFVector.
\item Optional arguments are depicted in square brackets $[*]$, where constants $c =1$ by default, functions are \texttt{NULL}-pointers by default and are treated as identity functors or simple multiplication functors.
\item Alternative argument of the form $\{b\in\mathbb{R}^n\,|\,i\in\mathbb{N}\}$ mean in the second case: $\vec{b}:=\vec{e}_i$.
\item The expression $b^*\in\mathbb{R}^n$ means a pointer to a \texttt{WorldVector<double>}.
\item The argument $div:=\mathbb{R}^{n\times n}\rightarrow\mathbb{R}^n$ is only interesting for error estimators and optional. Is should implement the divergence of the matrix function in the operator.
\item The argument \small{vec}$\langle*\rangle$ should be implemented as \texttt{std::vector$\langle*\rangle$}.
\item In the last Second-Order-Operator \texttt{GeneralParametric\_SOT}, the second argument $\vec{n}$ to $A$ is the elementnormal, especially for surface meshes.
\item In the last Second-Order-Operator \texttt{GeneralParametric\_*OT}, the second argument $\vec{n}$ to the functor is the elementnormal, especially for surface meshes.