diff --git a/DESCRIPTION b/DESCRIPTION
index 26272a2cb2d38e9560f5f26ec23482cee69b1ca4..18a0246572e655f772a97223c3949d67ec1966e6 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -1,7 +1,7 @@
 Package: sybil
 Type: Package
 Title: Efficient Constrained Based Modelling in R
-Version: 1.3.0
+Version: 1.3.1
 Date: 2015-06-17
 Authors@R: c(
 	     person(c("C.", "Jonathan"), "Fritzemeier", role = c("cre", "ctb"), email = "clausjonathan.fritzemeier@uni-duesseldorf.de"),
diff --git a/inst/NEWS.Rd b/inst/NEWS.Rd
index e9efbb8f82a311cf93d3b09efe4db0f6e826e4a3..414e4ca2e9331579f738b4fa20649d6723b40fea 100644
--- a/inst/NEWS.Rd
+++ b/inst/NEWS.Rd
@@ -6,6 +6,14 @@
 
 \newcommand{\CRANpkg}{\href{http://CRAN.R-project.org/package=#1}{\pkg{#1}}}
 
+\section{Changes in version 1.3.1 2015-08-06}{
+  \itemize{
+    \item \code{readTSVmod} had a mistake in the documentation about singletons.
+  }
+}
+
+% ---------------------------------------------------------------------------- %
+
 \section{Changes in version 1.3.0 2015-06-17}{
   \itemize{
     \item changed maintainer
diff --git a/man/readTSVmod.Rd b/man/readTSVmod.Rd
index cb200ffab5b69f131865a42cd05290d911d758f2..a75b5e324469369ef6f4c46c47897c26dbbdcdb6 100644
--- a/man/readTSVmod.Rd
+++ b/man/readTSVmod.Rd
@@ -314,7 +314,7 @@
   stoichiometric matrix \eqn{S} is used. Sums of rows gives the vector of
   metabolite usage, each element is the number of reactions a metabolite
   participates.  A single metabolite (singleton) is a metabolite with a row sum
-  of zero. All columns in \eqn{S} (reactions) containing singleton metabolites
+  of one. All columns in \eqn{S} (reactions) containing singleton metabolites
   will be set to zero. And again, singleton metabolites will be searched until
   none are found.