diff --git a/07-clifford1one/clase-15/README.md b/07-clifford1one/clase-15/README.md
index c4e5f6c6..ad57e6f5 100644
--- a/07-clifford1one/clase-15/README.md
+++ b/07-clifford1one/clase-15/README.md
@@ -1 +1,13 @@
-# clase-15
+# PREclase-15
+
+Links relevantes
+
+https://processing.org/reference/char.html
+
+https://processing.org/reference/Array.html
+
+https://processing.org/tutorials/arrays
+
+https://processing.org/examples/array.html
+
+https://forum.processing.org/one/topic/converting-a-string-to-an-array-of-chars