diff --git a/process.jl b/process.jl
index 09788bb..9d533a4 100644
--- a/process.jl
+++ b/process.jl
@@ -7,6 +7,11 @@ stl = load(raw"C:\Users\albig\Downloads\cubeblender.stl")
 # stl = load(raw"C:\Coding\stl_read\3DBenchy.stl")
 
 function get_mass_properties(triangles)
+	"""
+	Reference:
+		https://github.com/WoLpH/numpy-stl/blob/42b6c67324e13b8712af6730f77e5e9544ef63b0/stl/base.py#L362
+		https://www.geometrictools.com/Documentation/PolyhedralMassProperties.pdf
+	"""
     x = reduce(hcat, [[v[1] for v in tri] for tri in triangles])'
     y = reduce(hcat, [[v[2] for v in tri] for tri in triangles])'
     z = reduce(hcat, [[v[3] for v in tri] for tri in triangles])'