diff --git a/pypop7/optimizers/es/cmaes.py b/pypop7/optimizers/es/cmaes.py
index 9e301d008..4e5dfe654 100644
--- a/pypop7/optimizers/es/cmaes.py
+++ b/pypop7/optimizers/es/cmaes.py
@@ -45,7 +45,8 @@ class CMAES(ES):
        <https://arc.aiaa.org/doi/10.2514/1.C035054>`_, `[Yang et al., 2019, Journal of Aircraft]
        <https://arc.aiaa.org/doi/full/10.2514/1.C034873>`_, `[Ong et al., 2019, PLOS Computational Biology]
        <https://journals.plos.org/ploscompbiol/article?id=10.1371/journal.pcbi.1006993>`_, `[Zhang et al., 2017, Science]
-       <https://www.science.org/doi/full/10.1126/science.aal5054>`_, `[Loshchilov&Hutter, 2016]
+       <https://www.science.org/doi/full/10.1126/science.aal5054>`_, `[Wei&Mahadevan, 2016, Soft Matter]
+       <https://pubs.rsc.org/en/content/articlehtml/2016/sm/c5sm01597a>`_, `[Loshchilov&Hutter, 2016]
        <https://arxiv.org/abs/1604.07269>`_, `[Molinari et al., 2014, AIAAJ]
        <https://arc.aiaa.org/doi/full/10.2514/1.J052715>`_, `[Melton, 2014, Acta Astronautica]
        <https://www.sciencedirect.com/science/article/pii/S0094576514002318>`_, `[Khaira et al., 2014, ACS Macro Lett.]