diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 83b63fb..f7d9634 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -36,4 +36,7 @@ jobs:
         run: |
           uv sync
           uv run pre-commit run --all
-          uv run pytest
+          uv run pytest ./tests
+          uv run mypy ./src
+          uv run ruff check
+          uv run ruff format --check
diff --git a/pyproject.toml b/pyproject.toml
index bd8ca4c..e825d7f 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -113,3 +113,16 @@ build-backend = "hatchling.build"
 
 [tool.hatch.version]
 path = "src/bibx/__init__.py"
+
+[tool.tox]
+requires = ["tox>=4.24.2"]
+env_list = ["3.9", "3.10", "3.11", "3.12", "3.13"]
+
+[tool.tox.env_run_base]
+deps = [
+    "pytest>=8.3.5",
+    "ruff>=0.9.10",
+    "mypy~=1.9.0",
+    "types-requests>=2.32.0.20241016",
+]
+commands = [["ruff", "check"], ["pytest", "tests/"], ["mypy", "src/"]]
diff --git a/src/bibx/builders/openalex.py b/src/bibx/builders/openalex.py
index 2f31583..63e608e 100644
--- a/src/bibx/builders/openalex.py
+++ b/src/bibx/builders/openalex.py
@@ -94,6 +94,12 @@ def _extract_doi(url: str) -> str:
 
     @classmethod
     def _work_to_article(cls, work: Work) -> Article:
+        journal = None
+        if work.primary_location and work.primary_location.source:
+            journal = work.primary_location.source.display_name
+        permalink = None
+        if work.primary_location and work.primary_location.landing_page_url:
+            permalink = work.primary_location.landing_page_url
         article = Article(
             label=work.id,
             ids={
@@ -105,16 +111,12 @@ def _work_to_article(cls, work: Work) -> Article:
             authors=[cls._invert_name(a.author.display_name) for a in work.authorships],
             year=work.publication_year,
             title=work.title,
-            journal=(
-                work.primary_location
-                and work.primary_location.source
-                and work.primary_location.source.display_name
-            ),
+            journal=journal,
             volume=work.biblio.volume,
             issue=work.biblio.issue,
             page=work.biblio.first_page,
             doi=cls._extract_doi(work.doi) if work.doi else None,
-            _permalink=work.primary_location and work.primary_location.landing_page_url,
+            _permalink=permalink,
             times_cited=work.cited_by_count,
             references=[cls._reference_to_article(r) for r in work.referenced_works],
             keywords=[k.display_name for k in work.keywords],
diff --git a/src/bibx/builders/scopus_csv.py b/src/bibx/builders/scopus_csv.py
index 509807b..5950bc0 100644
--- a/src/bibx/builders/scopus_csv.py
+++ b/src/bibx/builders/scopus_csv.py
@@ -91,11 +91,11 @@ def build(self) -> Collection:
         articles = self._articles_from_files()
         return Collection(articles=Collection.deduplicate_articles(list(articles)))
 
-    def _articles_from_files(self) -> Generator[Article]:
+    def _articles_from_files(self) -> Generator[Article, None, None]:
         for file in self._files:
             yield from self._parse_file(file)
 
-    def _parse_file(self, file: TextIO) -> Generator[Article]:
+    def _parse_file(self, file: TextIO) -> Generator[Article, None, None]:
         reader = csv.DictReader(file)
         for row in reader:
             datum = Row.model_validate(row)
diff --git a/src/bibx/builders/wos.py b/src/bibx/builders/wos.py
index 43273ac..afdce0c 100644
--- a/src/bibx/builders/wos.py
+++ b/src/bibx/builders/wos.py
@@ -369,7 +369,7 @@ def _parse(cls, key: str, value: list[str]) -> dict:
         if key in cls.FIELDS:
             field = cls.FIELDS[key]
             parsed_value = field.parse(value)
-            return {new_key: parsed_value for new_key in [field.key, *field.aliases]}
+            return dict.fromkeys([field.key, *field.aliases], parsed_value)
 
         logger.debug("Found an unknown field with key %s and value %s", key, value)
         return {key: _ident(value)}
diff --git a/src/bibx/collection.py b/src/bibx/collection.py
index fc33677..59803eb 100644
--- a/src/bibx/collection.py
+++ b/src/bibx/collection.py
@@ -74,7 +74,7 @@ def _uniqe_articles_by_id(cls, articles: list[Article]) -> dict[str, Article]:
                     articles.append(article)
                     visited.add(id(article))
             merged = reduce(Article.merge, articles)
-            article_by_id.update({id_: merged for id_ in ids})
+            article_by_id.update(dict.fromkeys(ids, merged))
 
         return article_by_id
 
diff --git a/stubs/bibtexparser/bparser.pyi b/stubs/bibtexparser/bparser.pyi
new file mode 100644
index 0000000..41698b4
--- /dev/null
+++ b/stubs/bibtexparser/bparser.pyi
@@ -0,0 +1,2 @@
+class BibDatabase:
+    entries: list[dict]
diff --git a/stubs/networkx/algorithms/__init__.pyi b/stubs/networkx/algorithms/__init__.pyi
new file mode 100644
index 0000000..e69de29
diff --git a/stubs/networkx/algorithms/community/__init__.pyi b/stubs/networkx/algorithms/community/__init__.pyi
new file mode 100644
index 0000000..e69de29
diff --git a/stubs/networkx/classes/__init__.pyi b/stubs/networkx/classes/__init__.pyi
new file mode 100644
index 0000000..e69de29
diff --git a/stubs/networkx/classes/reportviews.pyi b/stubs/networkx/classes/reportviews.pyi
new file mode 100644
index 0000000..e53edcc
--- /dev/null
+++ b/stubs/networkx/classes/reportviews.pyi
@@ -0,0 +1,6 @@
+from collections.abc import Iterator, Mapping, Set
+
+class NodeView(Mapping, Set):
+    def __getitem__(self, key: str, /) -> dict: ...
+    def __iter__(self) -> Iterator[str]: ...
+    def __len__(self) -> int: ...