Change of variable $#1$ to $#2$ and $#3$ to $#4$ and $#5$ to $#6$ and $#7$ to $#8$ and $#9$ to $#10$ and $#11$ to $#12$ in Eq.~ref{eq:#13}; yields Eq.~ref{eq:#14}.
Substitute LHS of Eq.~ref{eq:#1} and LHS of Eq.~ref{eq:#2} and LHS of Eq.~ref{eq:#3} and LHS of Eq.~ref{eq:#4} and LHS of Eq.~ref{eq:#5} into Eq.~ref{eq:#6}; yields Eq.~ref{eq:#7}.
Substitute LHS of Eq.~ref{eq:#1} and LHS of Eq.~ref{eq:#2} and LHS of Eq.~ref{eq:#3} and LHS of Eq.~ref{eq:#4} into Eq.~ref{eq:#5}; yields Eq.~ref{eq:#6}.
Substitute LHS of Eq.~ref{eq:#1} and LHS of Eq.~ref{eq:#2} and LHS of Eq.~ref{eq:#3} and LHS of Eq.~ref{eq:#4} and LHS of Eq.~ref{eq:#5} and LHS of Eq.~ref{eq:#6} into Eq.~ref{eq:#7}; yields Eq.~ref{eq:#8}.