diff --git a/Doc/FFCatalog/FFCatalog.pdf b/Doc/FFCatalog/FFCatalog.pdf
index e4f3a8032e203c04f4b98a6074bebbf2afce3536..4be37405598448019bec5cc36d8d3ecde9cca021 100644
Binary files a/Doc/FFCatalog/FFCatalog.pdf and b/Doc/FFCatalog/FFCatalog.pdf differ
diff --git a/Doc/FFCatalog/FormFactors.tex b/Doc/FFCatalog/FormFactors.tex
index 122a937ae2e7569f73907b4cd7a7935523c80704..213887b92ce448dab68d5aefd4818639a7985434 100644
--- a/Doc/FFCatalog/FormFactors.tex
+++ b/Doc/FFCatalog/FormFactors.tex
@@ -684,7 +684,8 @@ The integral over $\varphi$ vanishes except for $n=2k$. Hence
   = 2\pi \sum_{k=0}^\infty(-)^k\frac{{\sqrt{ab}\,}^{2k}}{k!k!}
   = 2\pi J_0\left(rq_\parallel\right).
 \end{equation}
-Integration over~$r$ then yields the in-plane contribution to the form factor~$F(\q)$.
+To compute the ensueing radial integral $\int \d r r J_0(rq_\parallel)$,
+use $t J_0(t)= \d[t J_1(t)]/\d t$ \cite[Formula~9.1.30a]{AbSt64}.
 
 
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