diff --git a/ACEFormat.pdf b/ACEFormat.pdf
index 54a9f62..1f449b0 100644
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diff --git a/src/ContinuousEnergyNeutron.tex b/src/ContinuousEnergyNeutron.tex
index 1ac5198..e2c8261 100644
--- a/src/ContinuousEnergyNeutron.tex
+++ b/src/ContinuousEnergyNeutron.tex
@@ -831,21 +831,40 @@ \subsubsubsection{\var{LAW}=61---Like \var{LAW}=44, but tabular angular distribu
 \end{description}
 
 \subsubsubsection{\var{LAW}=66---$N$-body phase space distribution}\label{sec:LAW66}
-\begin{LAWTable}{\var{LAW}=66 (From ENDF-6 \MF=6 \var{LAW}=6)}
-  \var{LDAT}(1) & \var{NPSX} & Number of bodies in the phase space \\
-  \var{LDAT}(2) & $A_{P}$ & Total mass ratio for the \var{NPSX} particles.
-  \label{tab:LAW66}
-\end{LAWTable}
+\begin{ThreePartTable}
+	\begin{TableNotes}
+		\item[$\dagger$] \label{tn:LAW66FractionInterpolationScheme}
+		\begin{description}
+			\item[\var{INTT}=1] histogram distribution, and
+			\item[\var{INTT}=2] linear-linear distribution.
+		\end{description}
+	\end{TableNotes}
+	\begin{LAWTable}{\var{LAW}=66 (From ENDF-6 \MF=6 \var{LAW}=6)}
+		\var{LDAT}(1) & \var{NPSX} & Number of bodies in the phase space \\
+		\var{LDAT}(2) & $A_{P}$ & Total mass ratio for the \var{NPSX} particles \\
+		\var{LDAT}(3) & \var{INTT} & Interpolation flag\tnotex{tn:LAW66FractionInterpolationScheme} \\
+		\var{LDAT}(4) & $N_{P}$ & Number of points in the distribution \\
+		\var{LDAT}(5) & $T(j),j=1,\ldots,N_{P}$ & Fraction of max energy \\
+		\var{LDAT}(5+$N_{P}$)  & $\PDF(j),j=1,\ldots,N_{P}$ & Probability density function \\
+		\var{LDAT}(5+$2N_{P}$) & $\CDF(j),j=1,\ldots,N_{P}$ & Cumulative density function
+		\label{tab:LAW66}
+	\end{LAWTable}
+\end{ThreePartTable}
 
-The outgoing energy is
+The outgoing center-of-mass energy is
 \begin{align}
-  E_{\mathrm{out}} &= T(\xi)E_{i}^{\mathrm{max}} \\
+  E_{\mathrm{out}}^{\mathrm{CM}} &= TE_{i}^{\mathrm{max}} \\
   \intertext{where}
-  E_{i}^{\mathrm{max}} &= \frac{A_{p}-1}{A_{p}}\left( \frac{A}{A+1}E_{\mathrm{in}}+Q \right) \\
-  \intertext{and $T(\xi)$ is sampled from:}
-  P_{i}(\mu,E_{\mathrm{in}},T) &= C_{n}\sqrt{T}\left( E_{i}^{\mathrm{max}}-T \right)^{3n/2-4}
+  E_{i}^{\mathrm{max}} &= \frac{A_{p}-1}{A_{p}}\left( \frac{A}{A+1}E_{\mathrm{in}}+Q \right). \\
+  \intertext{With $n=\mathrm{NPSX}$, the analytic distribution for $T$ is:}
+  P(T) &= C_{n}\sqrt{T}\left( 1 - T \right)^{3n/2-4} \\
+  \intertext{where $C_{n}$ is taken to be:}
+  C_{n=3} &= \frac{8}{\pi}\\
+  C_{n=4} &= \frac{105}{16} \\
+  C_{n=5} &= \frac{256}{7\pi}
   \label{eq:LAW66}
 \end{align}
+The cosine of the center-of-mass scattering angle, $\mu_{\mathrm{CM}}$, is isotropic.
 
 \subsubsubsection{\var{LAW}=67---Laboratory Angle-Energy Law}\label{sec:LAW67}
 \begin{ThreePartTable}