diff --git a/biblio.bib b/biblio.bib
index 440158d..950df3d 100644
--- a/biblio.bib
+++ b/biblio.bib
@@ -655,3 +655,18 @@ @article{jiAirStableOrganicRadicals2020
 	file = {/home/pierre/Zotero/storage/8GRINQS5/Ji et al. - 2020 - Air-Stable Organic Radicals New-Generation Materi.pdf;/home/pierre/Zotero/storage/I6ZDH48P/adma.html}
 }
 
+@article{hanschSurveyHammettSubstituent1991,
+	title = {A Survey of {{Hammett}} Substituent Constants and Resonance and Field Parameters},
+	author = {Hansch, {\relax Corwin}. and Leo, A. and Taft, R. W.},
+	year = {1991},
+	month = mar,
+	journal = {Chemical Reviews},
+	volume = {91},
+	number = {2},
+	pages = {165--195},
+	publisher = {American Chemical Society},
+	issn = {0009-2665},
+	doi = {10.1021/cr00002a004},
+	urldate = {2024-05-24},
+	file = {/home/pierre/Zotero/storage/5HQ2AU8W/Hansch et al. - 1991 - A survey of Hammett substituent constants and reso.pdf}
+}
diff --git a/nitroxides_SI.tex b/nitroxides_SI.tex
index 2e3edea..8b6542a 100644
--- a/nitroxides_SI.tex
+++ b/nitroxides_SI.tex
@@ -135,8 +135,23 @@
 
 \begin{figure}[!h]
 	\centering
+	\begin{tblr}{lcc}
+		\hline
+		& $\sigma_p$ & $\sigma_m$ \\
+		\hline
+		\ce{COOH} & 0.45 &0.37 \\
+		\ce{NH2} & -0.66 & -0.16 \\
+		\ce{OMe} & -0.27 & 0.12 \\
+		\ce{OH} & -0.37 & 0.12 \\
+		\ce{NH3+} & 0.60 & 0.86 \\
+		\ce{Br} & 0.23 & 0.39 \\
+		$>$\ce{C=O} & 0.50 & --- \\
+		\ce{C=C-CONH2} & 0.36 & 0.28 \\
+		\ce{NO2} & 0.78 & 0.71 \\
+		\hline
+	\end{tblr}
 	\includegraphics [width=\linewidth]{FigureS4}
-	\caption{Correlation between absolute oxidation (left) and reduction (right) and the Hammet constant of their substituent for compounds of the P5O (black markers) and P6O (blue markers) families.}
+	\caption{Correlation between absolute oxidation (left) and reduction (right) and the Hammet constant of their substituent (para, $\sigma_p$, or meta, $\sigma_m$, from Ref.~\cite{hanschSurveyHammettSubstituent1991} and reported in the table) for compounds of the P5O (black markers, correlated with $\sigma_m$) and P6O (blue markers, with correlated with $\sigma_p$) families.}
 \end{figure}
 
 \clearpage