diff --git a/PapersCited.py b/PapersCited.py
index f7e1e64..f5dcad2 100644
--- a/PapersCited.py
+++ b/PapersCited.py
@@ -10,7 +10,7 @@
 import xlsxwriter
 
 # regex in Python
-import re
+import regex
 
 # GUI elements - for the file dialog. Explicitly import the filedialog submodule.
 import tkinter
@@ -21,9 +21,9 @@
 
 class RegexPatterns:
     # Phrases that make up regex patterns for detecting citations
-    letter_character = "[a-zšđčćžäöüñáéíóúç'’\\-]"
-    letter_uppercase = letter_character.upper()
-    rest_of_word = letter_character[:-1] + letter_uppercase[1:] + "+"
+    letter_lowercase = "\\p{Ll}"
+    letter_uppercase = "\\p{Lu}"
+    rest_of_word = "(?:\\p{L}|['’\\-])+"
     # For years - must be exactly four digits, not followed by another digit.
     years = "(?:\\(?\\d{4}(?!\\d)[abcd]?,?\\s?;?\\s?)+"
     phrase_and = " +(?:and+|[i&]+) +"
@@ -70,7 +70,6 @@ class PhrasesToChange:
       "^za[ ,]"
     ]
     english_excluded_phrases = [
-      "^-",
       "^a[ ,]",
       "^an[ ,]",
       "^at[ ,]",
@@ -110,12 +109,12 @@ def drop_excluded_phrases(self):
             PhrasesToChange.english_excluded_phrases
         for index_no, citation in enumerate(self.citations):
             for phrase in excluded_phrases:
-                match = re.search(
+                match = regex.search(
                     phrase,
                     citation,
-                    re.IGNORECASE
+                    regex.IGNORECASE
                 )
-        # If a match is not found, the result of re.match is None
+        # If a match is not found, the result of regex.match is None
                 if match:
                     filtered_citations[index_no] = "__DELETE__"
         # Retain only citations that haven't been flagged
@@ -135,14 +134,14 @@ def _remove_extra_characters(self, allow_commas = False):
             # Remove leading and trailing spaces
             clean_citations[index_no] = clean_citations[index_no].strip()
             # Condense multiple spaces to a single one.
-            clean_citations[index_no] = re.sub(" +", " ", clean_citations[index_no])
+            clean_citations[index_no] = regex.sub(" +", " ", clean_citations[index_no])
         return(clean_citations)
     
     def _separate_name_year(self):
         citations = self.citations
         rx = RegexPatterns()
         # If letters and digits are "adjacent", put a space in between 
-        separated_citations = [re.sub("(" + rx.rest_of_word + ")(\\d\\d)", "\\g<1> \\g<2>", citation)\
+        separated_citations = [regex.sub("(" + rx.rest_of_word + ")(\\d\\d)", "\\g<1> \\g<2>", citation)\
             for citation in citations]
         return(separated_citations)
 
@@ -167,10 +166,10 @@ def _separate_multiple_years(self):
         extracted_citations = []
         
         for index_no, citation in enumerate(all_citations):
-            years = re.findall(pattern = single_year_pattern, string = citation)
+            years = regex.findall(pattern = single_year_pattern, string = citation)
             # findall always returns a list
             if len(years) > 1:
-                citation_start = re.sub(all_years_pattern, "", citation)
+                citation_start = regex.sub(all_years_pattern, "", citation)
                 all_citations[index_no] = "__DELETE__"
                 new_citations = [citation_start + year for year in years]
                 extracted_citations.extend(new_citations)
@@ -279,7 +278,7 @@ def read_document(filename):
 
 def get_matches_solo_author(text, drop_excluded_phrases = False):
     rx = RegexPatterns()
-    matches = re.findall(
+    matches = regex.findall(
         rx.letter_uppercase + rx.rest_of_word + "[\\s,(]+" + rx.years,
         text)
     matches = CitationType(matches)
@@ -289,7 +288,7 @@ def get_matches_solo_author(text, drop_excluded_phrases = False):
 def get_matches_two_authors(text, drop_excluded_phrases = False):
     # The second word doesn't have to be uppercase, to catch "suradnici".
     rx = RegexPatterns()
-    matches = re.findall(
+    matches = regex.findall(
         rx.letter_uppercase + rx.rest_of_word + rx.phrase_and +
         rx.rest_of_word + "[\\s,(]+" + rx.years,
         text)
@@ -299,7 +298,7 @@ def get_matches_two_authors(text, drop_excluded_phrases = False):
 
 def get_matches_author_et_al(text, drop_excluded_phrases = False):
     rx = RegexPatterns()
-    matches = re.findall(
+    matches = regex.findall(
         rx.letter_uppercase + rx.rest_of_word + "(?:" + rx.phrase_et_al + "|" + rx.phrase_i_sur + ")" + rx.years,
         text)
     matches = CitationType(matches)
@@ -311,7 +310,7 @@ def get_matches_three_authors(text, drop_excluded_phrases = False):
     # To remedy some, the first letter of the first two words must be capitalised.
     # The last doesn't, so it catches the term "suradnici" common for multiple authors.
     rx = RegexPatterns()
-    matches = re.findall(
+    matches = regex.findall(
         rx.letter_uppercase + rx.rest_of_word + "[\\s,]+" +
         rx.letter_uppercase + rx.rest_of_word + rx.phrase_and + 
         rx.rest_of_word + "[\\s,(]+" + rx.years,
@@ -323,7 +322,7 @@ def get_matches_three_authors(text, drop_excluded_phrases = False):
 def get_matches_two_surnames(text, drop_excluded_phrases = False):
     # Both names must me capitalised for it to be a valid citation.
     rx = RegexPatterns()
-    matches = re.findall(
+    matches = regex.findall(
         rx.letter_uppercase + rx.rest_of_word + "[\\s]+" +
         rx.letter_uppercase + rx.rest_of_word + "[\\s,(]+" + rx.years,
         text)
@@ -334,7 +333,7 @@ def get_matches_two_surnames(text, drop_excluded_phrases = False):
 def get_matches_two_surnames_et_al(text, drop_excluded_phrases = False):
     # Both names must me capitalised for it to be a valid citation.
     rx = RegexPatterns()
-    matches = re.findall(
+    matches = regex.findall(
         rx.letter_uppercase + rx.rest_of_word + "[\\s]+" +
         rx.letter_uppercase + rx.rest_of_word + "(?:" + rx.phrase_et_al + "|" + rx.phrase_i_sur + ")" + rx.years,
         text)
diff --git a/README.md b/README.md
index 081120e..ff7fb24 100644
--- a/README.md
+++ b/README.md
@@ -4,9 +4,9 @@ Write an Excel file containing all citations found in a document, so they can be
 
 ## Dependencies:
 This program was written using Python 3.9.12. It requires the following modules:
-textract, xlsxwriter
+textract, xlsxwriter, regex
 
-To install them in Powershell, type "*pip install textract*", followed by "*pip install xlsxwriter*".
+To install them in Powershell, type "*pip install textract*" and press Enter. After that, follow with "*pip install xlsxwriter*" and "*pip install regex*".
 
 # About:
 ***PapersCited*** is a small Python program designed to help you with **writing and reviewing reference lists** in your scientific articles. It reads through a document of your choice and takes a note every time something is cited. At the end, it writes all those citations in an Excel file in alphabetical order, omitting duplicate entries. 
diff --git a/tests/test_detecting_authors.py b/tests/test_detecting_authors.py
index 87e9b03..068aa57 100644
--- a/tests/test_detecting_authors.py
+++ b/tests/test_detecting_authors.py
@@ -70,12 +70,12 @@ def test_detecting_two_surnames_i_suradnika():
         ["Anić Babić i suradnika (2000"]
 
 def test_detecting_two_surnames_et_al():
-        test_string_semicolon = "This is the facts (Naked Truth et al., 1980). Also see Hard, 1980; Facts, 1989."
-        assert PapersCited.get_matches_two_surnames_et_al(test_string_semicolon).citations ==\
-            ["Naked Truth et al., 1980"]
-        test_croatian_i_sur = "Branjek i suradnici (1999) spominju rad Cvanjek i suradnika (1990) više puta (Dvanjek Erin i sur., 2010)"
-        assert PapersCited.get_matches_two_surnames_et_al(test_croatian_i_sur).citations ==\
-            ["Dvanjek Erin i sur., 2010"]
+    test_string_semicolon = "This is the facts (Naked Truth et al., 1980). Also see Hard, 1980; Facts, 1989."
+    assert PapersCited.get_matches_two_surnames_et_al(test_string_semicolon).citations ==\
+        ["Naked Truth et al., 1980"]
+    test_croatian_i_sur = "Branjek i suradnici (1999) spominju rad Cvanjek i suradnika (1990) više puta (Dvanjek Erin i sur., 2010)"
+    assert PapersCited.get_matches_two_surnames_et_al(test_croatian_i_sur).citations ==\
+        ["Dvanjek Erin i sur., 2010"]
 
 def test_program_works_with_no_citations_found():
     document = ""
@@ -146,6 +146,14 @@ def test_authors_should_be_capitalised_to_match():
     assert PapersCited.get_matches_two_authors(two_authors).citations == ["Bogus and Dogus, 3000"]
     # The second name can be lowercase to catch "suradnici".
     
+def test_new_foreign_characters():
+    text = "Bø (1999) and Yø (2000) and Så (2001)"
+    assert PapersCited.get_matches_solo_author(text).citations ==\
+        ["Bø (1999", "Yø (2000", "Så (2001"]
+    text_non_alphanumeric = "Bø's (1999) research cited Yø-yoma (2000)"
+    assert PapersCited.get_matches_solo_author(text_non_alphanumeric).citations ==\
+        ["Bø's (1999", "Yø-yoma (2000"]
+        
 def test_possesive_recognised_and_adjusted():
     possesive_text = "Listen to Cohen's (1999) talk."
     matches = PapersCited.get_matches_solo_author(possesive_text)
@@ -163,4 +171,4 @@ def test_surnames_apostrophe_s_recognised():
     matches = PapersCited.get_matches_solo_author(text)
     matches.cleanup()
     assert matches.citations == ["O'Samuel 1999", "O'Sullivan 2000"]
-    
\ No newline at end of file
+ 
\ No newline at end of file