diff --git a/.gitignore b/.gitignore
index cf6d470..b04cbdb 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,2 @@
 /*/*.bin
+/*/*.swp
diff --git a/03-bootsector-memory/README.md b/03-bootsector-memory/README.md
index c490139..fb63891 100644
--- a/03-bootsector-memory/README.md
+++ b/03-bootsector-memory/README.md
@@ -3,7 +3,7 @@
 The only goal of this lesson is to learn where the boot sector is stored
 
 Please open page 14 [of this document](
-http://www.cs.bham.ac.uk/~exr/lectures/opsys/10_11/lectures/os-dev.pdf)<sup>*</sup>
+http://www.cs.bham.ac.uk/~exr/lectures/opsys/10_11/lectures/os-dev.pdf)<sup>1</sup>
 and look at the figure with the memory layout.
 
 I could just go ahead and tell you that it starts at `0x7C00`, but it's
@@ -34,5 +34,5 @@ If you add or remove instructions, remember to compute the new offset of the X
 by counting the bytes, and replace `0x2d` with the new one.
 
 ~~~~~
-This whole tutorial is heavily inspired on that document. Please read the
+[1] This whole tutorial is heavily inspired on that document. Please read the
 root-level README for more information on that.