diff --git a/API_Reference.py b/API_Reference/API_Reference.py
similarity index 99%
rename from API_Reference.py
rename to API_Reference/API_Reference.py
index 69f6666..4be0fd8 100644
--- a/API_Reference.py
+++ b/API_Reference/API_Reference.py
@@ -522,7 +522,7 @@ guan.change_directory_by_replacement(current_key_word='code', new_key_word='data
 # Module 14: others
 
 # 拼接两个PDF文件
-guan.combine_two_pdf_files(input_file1='a.pdf', input_file2='b.pdf', output_file='combined_file.pdf')
+guan.combine_two_pdf_files(input_file_1='a.pdf', input_file_2='b.pdf', output_file='combined_file.pdf')
 
 # 通过Sci-Hub网站下载文献
 guan.download_with_scihub(address=None, num=1)
diff --git a/PyPI/LICENSE b/Source Code/PyPI/LICENSE
similarity index 100%
rename from PyPI/LICENSE
rename to Source Code/PyPI/LICENSE
diff --git a/PyPI/README.md b/Source Code/PyPI/README.md
similarity index 100%
rename from PyPI/README.md
rename to Source Code/PyPI/README.md
diff --git a/PyPI/pyproject.toml b/Source Code/PyPI/pyproject.toml
similarity index 100%
rename from PyPI/pyproject.toml
rename to Source Code/PyPI/pyproject.toml
diff --git a/PyPI/setup.cfg b/Source Code/PyPI/setup.cfg
similarity index 97%
rename from PyPI/setup.cfg
rename to Source Code/PyPI/setup.cfg
index b4aa80e..000152a 100644
--- a/PyPI/setup.cfg
+++ b/Source Code/PyPI/setup.cfg	
@@ -1,7 +1,7 @@
 [metadata]
 # replace with your username:
 name = guan
-version = 0.0.171
+version = 0.0.172
 author = guanjihuan
 author_email = guanjihuan@163.com
 description = An open source python package
diff --git a/PyPI/src/guan.egg-info/PKG-INFO b/Source Code/PyPI/src/guan.egg-info/PKG-INFO
similarity index 98%
rename from PyPI/src/guan.egg-info/PKG-INFO
rename to Source Code/PyPI/src/guan.egg-info/PKG-INFO
index 713c6b4..17e022c 100644
--- a/PyPI/src/guan.egg-info/PKG-INFO
+++ b/Source Code/PyPI/src/guan.egg-info/PKG-INFO	
@@ -1,6 +1,6 @@
 Metadata-Version: 2.1
 Name: guan
-Version: 0.0.171
+Version: 0.0.172
 Summary: An open source python package
 Home-page: https://py.guanjihuan.com
 Author: guanjihuan
diff --git a/PyPI/src/guan.egg-info/SOURCES.txt b/Source Code/PyPI/src/guan.egg-info/SOURCES.txt
similarity index 100%
rename from PyPI/src/guan.egg-info/SOURCES.txt
rename to Source Code/PyPI/src/guan.egg-info/SOURCES.txt
diff --git a/PyPI/src/guan.egg-info/dependency_links.txt b/Source Code/PyPI/src/guan.egg-info/dependency_links.txt
similarity index 100%
rename from PyPI/src/guan.egg-info/dependency_links.txt
rename to Source Code/PyPI/src/guan.egg-info/dependency_links.txt
diff --git a/PyPI/src/guan.egg-info/top_level.txt b/Source Code/PyPI/src/guan.egg-info/top_level.txt
similarity index 100%
rename from PyPI/src/guan.egg-info/top_level.txt
rename to Source Code/PyPI/src/guan.egg-info/top_level.txt
diff --git a/PyPI/src/guan/__init__.py b/Source Code/PyPI/src/guan/__init__.py
similarity index 99%
rename from PyPI/src/guan/__init__.py
rename to Source Code/PyPI/src/guan/__init__.py
index 19a3ed8..9f915cc 100644
--- a/PyPI/src/guan/__init__.py
+++ b/Source Code/PyPI/src/guan/__init__.py	
@@ -2,7 +2,7 @@
 
 # With this package, you can calculate band structures, density of states, quantum transport and topological invariant of tight-binding models by invoking the functions you need. Other frequently used functions are also integrated in this package, such as file reading/writing, figure plotting, data processing.
 
-# The current version is guan-0.0.171, updated on June 28, 2023.
+# The current version is guan-0.0.172, updated on July 02, 2023.
 
 # Installation: pip install --upgrade guan
 
@@ -3136,19 +3136,19 @@ def download_with_scihub(address=None, num=1):
 ## PDF
 
 # 拼接两个PDF文件
-def combine_two_pdf_files(input_file1='a.pdf', input_file2='b.pdf', output_file='combined_file.pdf'):
+def combine_two_pdf_files(input_file_1='a.pdf', input_file_2='b.pdf', output_file='combined_file.pdf'):
     import PyPDF2
     output_pdf = PyPDF2.PdfWriter()
-    with open(input_file1, 'rb') as file1:
+    with open(input_file_1, 'rb') as file1:
         pdf1 = PyPDF2.PdfReader(file1)
         for page in range(len(pdf1.pages)):
             output_pdf.add_page(pdf1.pages[page])
-    with open(input_file2, 'rb') as file2:
+    with open(input_file_2, 'rb') as file2:
         pdf2 = PyPDF2.PdfReader(file2)
         for page in range(len(pdf2.pages)):
             output_pdf.add_page(pdf2.pages[page])
-    with open(output_file, 'wb') as merged_file:
-        output_pdf.write(merged_file)
+    with open(output_file, 'wb') as combined_file:
+        output_pdf.write(combined_file)
 
 
 # 获取PDF文献中的链接。例如: link_starting_form='https://doi.org'