diff --git a/materials/sources/manifest.yml b/materials/sources/manifest.yml
new file mode 100644
index 0000000..ecf322a
--- /dev/null
+++ b/materials/sources/manifest.yml
@@ -0,0 +1,23 @@
+sources:
+  - filename: 2dm-3993.poscar
+    common_name: Graphene
+    lattice_type: HEX
+    space_group: P6/mmm
+    dimensionality: 2D
+    form_factor: Monolayer
+    source_id: 2dm-3993
+    source: 2dmatpedia
+    doi: 10.1038/s41597-019-0097-3
+    url: http://www.2dmatpedia.org/2dmaterials/doc/2dm-3993/
+  - filename: 2dm-4991.poscar
+    common_name: Hexagonal Boron Nitride
+    lattice_type: HEX
+    space_group: P6/mmm
+    dimensionality: 2D
+    form_factor: Monolayer
+    source_id: 2dm-4991
+    source: 2dmatpedia
+    doi: 10.1038/s41597-019-0097-3
+    url: http://www.2dmatpedia.org/2dmaterials/doc/2dm-4991/
+
+ 
\ No newline at end of file
diff --git a/pyproject.toml b/pyproject.toml
index c6be38b..e86b43c 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -22,7 +22,7 @@ dependencies = [
 ]
 
 [project.optional-dependencies]
-dev = ["pre-commit", "black", "ruff", "isort", "mypy", "pip-tools"]
+dev = ["pre-commit", "black", "ruff", "isort", "mypy", "pip-tools", "express-py"]
 tests = ["pytest", "pytest-cov", "pytest-mock"]
 
 # Entrypoint scripts can be defined here, see examples below.