diff --git a/src/analytical_solution.tex b/src/analytical_solution.tex
index 2038349..e1d613b 100644
--- a/src/analytical_solution.tex
+++ b/src/analytical_solution.tex
@@ -131,7 +131,9 @@ We nevertheless continue in full generality and approach the inverse
 Laplace transformation by expanding the BCF in terms of functions that
 have a simple Laplace transform. As we also use an exponential
 expansion in HOPS and are only interested in finite times, we may
-choose \(α_0(t)=\sum_{n=1}^N G_n \eu^{-W_n t - \i \varphi_n}\) with
+choose\footnote{This ansatz was found in private communication with
+  Valentin Link \orcidlink{0000-0002-1520-7931}.}
+\(α_0(t)=\sum_{n=1}^N G_n \eu^{-W_n t - \i \varphi_n}\) with
 \(W_n=\gamma_n + \i\delta_n\) and
 \(G_n, \varphi_n, \gamma_n,\delta_n\in\RR\) for \(t\geq 0\).