diff --git a/src/roadmaps/software-design-architecture/content/102-object-oriented-programming/101-paradigm-features/101-concrete-classes.md b/src/roadmaps/software-design-architecture/content/102-object-oriented-programming/101-paradigm-features/101-concrete-classes.md
index 78ae9d945..19b7f15c6 100644
--- a/src/roadmaps/software-design-architecture/content/102-object-oriented-programming/101-paradigm-features/101-concrete-classes.md
+++ b/src/roadmaps/software-design-architecture/content/102-object-oriented-programming/101-paradigm-features/101-concrete-classes.md
@@ -6,5 +6,4 @@ Concrete classes are used to provide specific implementation details for a group
 
 Learn more from the following resources:
 
-- [Concrete class in Java](https://www.geeksforgeeks.org/concrete-class-in-java/)
-- [Overview of Concrete Class](https://www.sciencedirect.com/topics/computer-science/concrete-class)
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+- [Concrete class in Java](https://www.geeksforgeeks.org/concrete-class-in-java/)
\ No newline at end of file