diff --git a/src/vonFoersterHazards.ipynb b/src/vonFoersterHazards.ipynb
index 9480221..0532782 100644
--- a/src/vonFoersterHazards.ipynb
+++ b/src/vonFoersterHazards.ipynb
@@ -8,7 +8,7 @@
     "\n",
     "## Preamble\n",
     "\n",
-    "*All [epidemiological models](https://en.wikipedia.org/wiki/Compartmental_models_in_epidemiology) are [Malthusian](https://en.wikipedia.org/wiki/Malthusian_growth_model). Fortunately [Malthus](https://en.wikipedia.org/wiki/Thomas_Robert_Malthus) was an optimist. His model postulates that a population will continuously approach [equilibrium](https://en.wikipedia.org/wiki/Ecological_stability) with the environment, without [overshoot](https://en.wikipedia.org/wiki/Overshoot_(population)) or [catastrophic collapse](https://en.wikipedia.org/wiki/Ecological_collapse).*\n",
+    "*All [epidemiological models](https://en.wikipedia.org/wiki/Compartmental_models_in_epidemiology) are [Malthusian](https://en.wikipedia.org/wiki/Malthusian_growth_model). Fortunately [Malthus](https://en.wikipedia.org/wiki/Thomas_Robert_Malthus) was an optimist. His model postulates that a population will continuously approach [equilibrium](https://en.wikipedia.org/wiki/Ecological_stability) with the environment, without [overshoot]( https://en.wikipedia.org/wiki/Overshoot_(population) ) or [catastrophic collapse](https://en.wikipedia.org/wiki/Ecological_collapse).*\n",
     "\n",
     "## Acknowledgment\n",
     "\n",