diff --git a/x86_64/README.md b/x86_64/README.md
index d11f550..e5e2683 100644
--- a/x86_64/README.md
+++ b/x86_64/README.md
@@ -13,3 +13,5 @@ nasm -g -f elf64 <file.asm>
 ld <object-files> -o <executable-name>  # Default
 gcc <object-files> -o <executable-name> # When using C library functions
 ```
+
+Based upon the work of [Carmo M de F Barbosa](https://gitlab.com/mcmfb/intro_x86-64)
\ No newline at end of file