diff --git a/linear_algebra/utilities/include/shell_sort.h.bak b/linear_algebra/utilities/include/shell_sort.h.bak
deleted file mode 100644
index cf241333ed0cb14f3d7b3704fb6dd51ac2c26bc9..0000000000000000000000000000000000000000
--- a/linear_algebra/utilities/include/shell_sort.h.bak
+++ /dev/null
@@ -1,60 +0,0 @@
-/*
- * Copyright (C) 2020 Zakaria Kasmi <zkasmi@inf.fu-berlin.de>
- *
- * This file is subject to the terms and conditions of the GNU Lesser General
- * Public License v2.1. See the file LICENSE in the top level directory for more
- * details.
- */
-
-/**
- * @ingroup utils
- * @{
- *
- * @file
- * @brief Implement the Shell sort algorithm.
- * @details The Shell sort algorithm is more convenient for devices with limited storage
- * capacity.
- *
- * @author Zakaria Kasmi <zkasmi@inf.fu-berlin.de>
- *
- * @}
- */
-
-#ifndef SHELL_SORT_H_
-#define SHELL_SORT_H_
-
-#include <stdint.h>
-#include "vector.h"
-
-/**
- * @brief Sort a data set of integers by using the Shell sort algorithm.
- *
- * @param[in] array[] pointer to the data set.
- * @param[in] length size of the data set.
- *
- */
-void int_shell_sort(int* array, int length);
-
-/**
- * @brief Sort a data set of type utils_t by using the Shell sort algorithm.
- *
- * @param[in] arr[] pointer to the data set.
- * @param[in] length size of the data set.
- *
- */
-void shell_sort(vector_t* arr, uint8_t length);
-
-/**
- * @brief Sort a data set of type utils_t by using the Shell sort algorithm.
- *
- * @param[in] arr[] pointer to the data set.
- * @param[in] length size of the data set.
- *
- */
-void double_shell_sort(vector_t* arr, uint8_t length);
-
-
-
-
-
-#endif /* SHELL_SORT_H_ */
diff --git a/linear_algebra/utilities/include/utils.h.bak b/linear_algebra/utilities/include/utils.h.bak
deleted file mode 100644
index 4316862c16abaaee8717f2fdb3800d83c2dcfac3..0000000000000000000000000000000000000000
--- a/linear_algebra/utilities/include/utils.h.bak
+++ /dev/null
@@ -1,176 +0,0 @@
-/*
- * Copyright (C) 2020 Zakaria Kasmi <zkasmi@inf.fu-berlin.de>
- *
- * This file is subject to the terms and conditions of the GNU Lesser General
- * Public License v2.1. See the file LICENSE in the top level directory for more
- * details.
- */
-
-/**
- * @ingroup utils
- * @{
- *
- * @file
- * @brief Utilities for linear algebra.
- * @details Utility-functions are needed by linear algebra-module as well as
- * other modules such as the position algorithm-module.
- *
- * @author Zakaria Kasmi <zkasmi@inf.fu-berlin.de>
- *
- * @}
- */
-
-#ifndef UTILS_H_
-#define UTILS_H_
-
-#include <inttypes.h>
-
-/** @brief Define the data type */
-#define utils_t double
-
-#ifndef utils_t
-#define utils_t double
-#endif
-
-/** @brief Define the pi-constant */
-#ifndef M_PI
-#define M_PI 3.14159265358979323846
-#endif
-
-/**
- * @brief Convert the angle from degrees to radians.
- *
- * @param[in] deg_angle angle in degrees.
- *
- * @return angle in radians.
- *
- */
-double utils_to_radian(double deg_angle);
-
-/**
- * @brief Compute the sine of a variable in degrees.
- * Calculate the sine of the variable deg_angle, which is expressed
- * in degrees.
- *
- * @param[in] deg_angle angle in degrees.
- *
- * @return sine value.
- *
- */
-double utils_sind(double deg_angle);
-
-/**
- * @brief Interchange the values of two variables of type uint8_t.
- *
- * @param[in] *a pointer to first variable.
- * @param[in] *b pointer to second variable.
- *
- */
-void utils_swap(uint8_t *a, uint8_t *b);
-
-/**
- * @brief Returns the greater of two real numbers.
- *
- * @param[in] a the first value to compare.
- * @param[in] b the second value to compare.
- *
- * @return the greater of a and b.
- *
- */
-double utils_max(double a, double b);
-
-/**
- * @brief Returns the smaller of two real numbers.
- *
- *
- * @param[in] a the first value to compare.
- * @param[in] b the second value to compare.
- *
- * @return the smaller of a and b.
- *
- */
-double utils_min(double a, double b);
-
-/**
- * @brief Returns the greater of two numbers from type uint8_t.
- *
- * @param[in] a the first value to compare.
- * @param[in] b the second value to compare.
- *
- * @return the greater of a and b.
- *
- */
-uint8_t utils_u8_max(uint8_t a, uint8_t b);
-
-/**
- * @brief Returns the smaller of two numbers from type uint8_t.
- *
- * @param[in] a the first value to compare.
- * @param[in] b the second value to compare.
- *
- * @return the smaller of a and b.
- *
- */
-uint8_t utils_u8_min(uint8_t a, uint8_t b);
-
-// Enables to use variable format string as well as argument lists
-// Fixing error: format not a string literal.
-
-/**
- * @brief Print by using variable format string as well as argument lists.
- * This function enables to print data by using a variable format
- * string as well as argument list. Furthermore, it avoids the error:
- * "format not a string literal", if printf is used.
- *
- * @param[in] *format_str format string.
- * @param[in] ... argument list.
- *
- */
-void utils_printf(char *format_str, ...);
-
-/**
- * @brief Compute the mean value of a data set.
- *
- * @param[in] arr_size size of the data set.
- * @param[in] in_arr[] pointer to the data set.
- *
- * @return the mean value of the data set.
- *
- */
-double utils_mean(uint8_t arr_size, double in_arr[]);
-
-/**
- * @brief Compute the moving average of a data set.
- *
- * @param[in] arr_size size of the data set.
- * @param[in] in_arr[] pointer to the data set.
- * @param[in] window_size window size.
- * @param[out] out_arr pointer to the values of the moving average.
- *
- */
-void utils_moving_average(uint8_t arr_size, double in_arr[], uint8_t window_size, double out_arr[]);
-
-
-/**
- * @brief Compute the median of a finite array of numbers.
- *
- * @param[in] arr[] pointer to the data set.
- * @param[in] length size of the data set.
- *
- * @return the median value of the data set.
- *
- */
-double utils_get_median(double arr[], uint8_t length);
-
-/**
- * @brief Compute the square root without under/overflow.
- *
- * @param[in] x first value.
- * @param[in] y second value.
- *
- * @return save square root.
- *
- */
-double utils_get_save_square_root(double x, double y);
-
-#endif /* UTILS_H_ */