ECC edits

src/Advanced/Error-Correcting Codes/main.tex

@@ -16,11 +16,6 @@
 \title{Error-Correcting Codes}
 \subtitle{Prepared by Mark on \today}
 
-
-% TODO:
-% ISBN section is tedious, could use some work.
-% Check problem 5
-
 \begin{document}
 
 	\maketitle

src/Advanced/Error-Correcting Codes/parts/00 detection.tex

@@ -131,7 +131,7 @@ Take a valid ISBN-13 and swap two adjacent digits. When will the result be a val
 
 \vfill
 
-\problem{}<isbnnocorrect>
+\problem{}<isbn-nocorrect>
 \texttt{978-008-2066-466} was a valid ISBN until I changed a single digit. \par
 Can you find the digit I changed? Can you recover the original ISBN?
 

src/Advanced/Error-Correcting Codes/parts/01 correction.tex

@@ -1,6 +1,6 @@
 \section{Error Correction}
 
-As we saw in \ref{isbnnocorrect}, the ISBN check-digit scheme does not allow us to correct errors. \par
+As we saw in \ref{isbn-nocorrect}, the ISBN check-digit scheme does not allow us to correct errors. \par
 QR codes feature a system that does. \par
 
 \vspace{1mm}