diff --git a/trees_and_graphs/dijkstra_adj_matrix.py b/trees_and_graphs/dijkstra_adj_matrix.py
index e7a7b15..732e9c9 100644
--- a/trees_and_graphs/dijkstra_adj_matrix.py
+++ b/trees_and_graphs/dijkstra_adj_matrix.py
@@ -1,3 +1,7 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+# author: bt3gl
+
 # dijkstra's single source shortest path algorithm
 # with adjacency matrix representation