diff --git a/paper/paper.md b/paper/paper.md
index 816ec83..369c3a5 100644
--- a/paper/paper.md
+++ b/paper/paper.md
@@ -58,7 +58,7 @@ A concise comparison between `pyrimidine` and several popular frameworks is prov
 
 : Comparison of the popular genetic algorithm frameworks. \label{frameworks}
 
-`Tpot`/`gama`[@olson; @pieter], `gplearn`/`pysr`, and `scikit-opt` follow the scikit-learn style [@sklearn_api], providing fixed APIs with limited extensibility. They are merely serving their respective fields effectively (as well as `NEAT`[@neat-python]).
+`Tpot`/`gama` [@olson; @pieter], `gplearn`/`pysr`, and `scikit-opt` follow the scikit-learn style [@sklearn_api], providing fixed APIs with limited extensibility. They are merely serving their respective fields effectively (as well as `NEAT`[@neat-python]).
 
 `DEAP` is feature-rich and mature. However, it primarily adopts a tedious meta-programming style. Some parts of the source code lack sufficient decoupling, limiting its extensibility. `Gaft` is a highly object-oriented software with excellent scalability, but it is currently inactive.