diff --git a/math/fibonacci_sum.cpp b/math/fibonacci_sum.cpp
index 4a3daa785..e8485b20d 100644
--- a/math/fibonacci_sum.cpp
+++ b/math/fibonacci_sum.cpp
@@ -2,9 +2,9 @@
  * @file
  * @brief An algorithm to calculate the sum of Fibonacci Sequence: \f$\mathrm{F}(n) + \mathrm{F}(n+1) + .. + \mathrm{F}(m)\f$
  * @details An algorithm to calculate the sum of Fibonacci Sequence: \f$\mathrm{F}(n) + \mathrm{F}(n+1) + .. + \mathrm{F}(m)\f$ where \f$\mathrm{F}(i)\f$
- * denotes the i-th Fibonacci Number . Note that F(0) = 0 and F(1) = 1. 
+ * denotes the i-th Fibonacci Number . Note that F(0) = 0 and F(1) = 1.
  * The value of the sum is calculated using matrix exponentiation.
- *
+ * @source https://stackoverflow.com/questions/4357223/finding-the-sum-of-fibonacci-numbers
  * @author [Sarthak Sahu](https://github.com/SarthakSahu1009)
  */
 
@@ -17,81 +17,81 @@
  * @brief Mathematical algorithms
  */
 namespace math {
-/**
- * @namespace fibonacci_sum
- * @brief Functions for the sum of the Fibonacci Sequence: \f$\mathrm{F}(n) + \mathrm{F}(n+1) + .. + \mathrm{F}(m)\f$
- */
-namespace fibonacci_sum {
-    
     /**
-     * Function to multiply two matrices
-     * @param T matrix 1
-     * @param A martix 2
-     * @returns resultant matrix
+     * @namespace fibonacci_sum
+     * @brief Functions for the sum of the Fibonacci Sequence: \f$\mathrm{F}(n) + \mathrm{F}(n+1) + .. + \mathrm{F}(m)\f$
      */
-    std::vector<std::vector<int> > multiply(std::vector<std::vector<int> > T, std::vector<std::vector<int> > A) {
-    
-        std::vector<std::vector<int> > result(2,std::vector<int>(2));
-        
-        // multiplying matrices
-        for(int i=0;i<2;i++) {
-            for(int j=0;j<2;j++) {
-                result[i][j]=0;
-                for(int k=0;k<2;k++) {
-                    result[i][j]=(result[i][j]+(T[i][k]*A[k][j]));
+    namespace fibonacci_sum {
+
+        /**
+         * Function to multiply two matrices
+         * @param T matrix 1
+         * @param A martix 2
+         * @returns resultant matrix
+         */
+        std::vector<std::vector<int> > multiply(std::vector<std::vector<int> > T, std::vector<std::vector<int> > A) {
+
+            std::vector<std::vector<int> > result(2,std::vector<int>(2));
+
+            // multiplying matrices
+            for(int i=0;i<2;i++) {
+                for(int j=0;j<2;j++) {
+                    result[i][j]=0;
+                    for(int k=0;k<2;k++) {
+                        result[i][j]=(result[i][j]+(T[i][k]*A[k][j]));
+                    }
                 }
             }
+
+            return result;
         }
-        
-        return result;
-    }
- 
-    /**
-     * Function to compute A^n where A is a matrix.
-     * @param T matrix
-     * @param ex power
-     * @returns resultant matrix
-     */
-    std::vector<std::vector<int> > power(std::vector<std::vector<int> > T, int ex) {
-        
-        std::vector<std::vector<int> > A{{1,1},{1,0}};
-        if(ex == 0 || ex == 1) {
+
+        /**
+         * Function to compute A^n where A is a matrix.
+         * @param T matrix
+         * @param ex power
+         * @returns resultant matrix
+         */
+        std::vector<std::vector<int> > power(std::vector<std::vector<int> > T, int ex) {
+
+            std::vector<std::vector<int> > A{{1,1},{1,0}};
+            if(ex == 0 || ex == 1) {
+                return T;
+            }
+
+            T = power(T,ex/2);
+            T = multiply(T,T);
+            if(ex&1) {
+                T = multiply(T,A);
+            }
             return T;
         }
-        
-        T = power(T,ex/2);
-        T = multiply(T,T);
-        if(ex&1) {
-            T = multiply(T,A);
+
+        /**
+         * Function to compute sum of fibonacci sequence from 0 to n.
+         * @param n number
+         * @returns int ans, the sum of sequence
+         */
+        int result(int n) {
+            std::vector<std::vector<int> > T{{1,1},{1,0}};
+            T = power(T,n);
+            int ans=T[0][1];
+            ans = (ans - 1);
+            return ans;
         }
-        return T;
-    }
-    
-    /**
-     * Function to compute sum of fibonacci sequence from 0 to n.
-     * @param n number
-     * @returns int ans, the sum of sequence
-     */
-    int result(int n) {
-        std::vector<std::vector<int> > T{{1,1},{1,0}};
-        T = power(T,n);
-        int ans=T[0][1];
-        ans = (ans - 1);
-        return ans;
-    }
-    
-    /**
-     * Function to compute sum of fibonacci sequence from n to m.
-     * @param n start of sequence
-     * @param m end of sequence
-     * @returns int the sum of sequence
-     */
-    int fiboSum(int n,int m){
-        return (result(m+2) - result(n+1));
-    }
-}  // namespace fibonacci_sum
+
+        /**
+         * Function to compute sum of fibonacci sequence from n to m.
+         * @param n start of sequence
+         * @param m end of sequence
+         * @returns int the sum of sequence
+         */
+        int fiboSum(int n,int m){
+            return (result(m+2) - result(n+1));
+        }
+    }  // namespace fibonacci_sum
 }  // namespace math
- 
+
 /**
  * Function for testing fiboSum function.
  * test cases and assert statement.
@@ -99,30 +99,30 @@ namespace fibonacci_sum {
 */
 static void test() {
     int n = 0, m = 3;
-    int test_1 = math::fiboSum(n,m);
+    int test_1 = math::fibonacci_sum::fiboSum(n,m);
     assert(test_1 == 4);
     std::cout << "Passed Test 1!" << std::endl;
 
     n = 3; m = 5;
-    int test_2 = math::fiboSum(n,m);
+    int test_2 = math::fibonacci_sum::fiboSum(n,m);
     assert(test_2 == 10);
     std::cout << "Passed Test 2!" << std::endl;
 
     n = 5; m = 7;
-    int test_3 = math::fiboSum(n,m);
+    int test_3 = math::fibonacci_sum::fiboSum(n,m);
     assert(test_3 == 26);
     std::cout << "Passed Test 3!" << std::endl;
 
     n = 7; m = 10;
-    int test_4 = math::fiboSum(n,m);
+    int test_4 = math::fibonacci_sum::fiboSum(n,m);
     assert(test_4 == 123);
     std::cout << "Passed Test 4!" << std::endl;
 
     n = 9; m = 12;
-    int test_5 = math::fiboSum(n,m);
+    int test_5 = math::fibonacci_sum::fiboSum(n,m);
     assert(test_5 == 322);
     std::cout << "Passed Test 5!" << std::endl;
-} 
+}
 
 /**
  * @brief Main function
@@ -130,6 +130,6 @@ static void test() {
  */
 int main()
 {
-    test();
+    test(); // execute the tests
     return 0;
 }