Update references and typo

Signed-off-by: Riccardo Finotello <riccardo.finotello@gmail.com>

sec/part1/introduction.tex

@@ -1280,7 +1280,7 @@ The field $\cA^a$ forms a vector representation of the group \SO{D-1-p} and from
 \end{figure}
 
 It is also possible to add non dynamical degrees of freedom (\dof) to the open string endpoints.
-They are known as \emph{Chan-Paton factors}~\cite{Paton:1969:GeneralizedVenezianoModel}.
+They are known as \emph{Chan-Paton factors}~\cite{Chan:1969:GeneralizedVenezianoModel}.
 They have no dynamics and do not spoil Poincaré or conformal invariance in the action of the string.
 Each state can then be labelled by $i$ and $j$ running from $1$ to $N$.
 Matrices $\tensor{\lambda}{^a_{ij}}$ thus form a basis for expanding wave functions and states:

sec/part2/divergences.tex

@@ -3547,7 +3547,7 @@ Differently from the \nbo, in this case the orbifold generator~\eqref{eq:nbo_kil
     \kappa & = - 2 \pi i \Delta\, J_{+2} - 2 \pi i R P_3
     \\
     & =
-    2 \pi\, (\Delta\, \ipd{z} + R,\ \ipd{3}).
+    2 \pi\, (\Delta\, \ipd{z} + R\, \ipd{3}).
   \end{split}
 \end{equation}
 with metric