diff --git a/CONTRIBUTORS.md b/CONTRIBUTORS.md
index 38d35f4d..1d232df9 100644
--- a/CONTRIBUTORS.md
+++ b/CONTRIBUTORS.md
@@ -12,7 +12,7 @@
 - stag019 <stag019@gmail.com>
 - Antonio Niño Díaz <antonio_nd@outlook.com>
 - Eldred "ISSOtm" Habert <me@eldred.fr>
-- Sylvie "Rangi" Oukaour <http://github.com/Rangi42>
+- Sylvie "Rangi" Oukaour <https://github.com/Rangi42>
 
 ## Other contributors
 
@@ -22,7 +22,7 @@
 - David Brotz <dbrotz007@gmail.com>
 - James "JL2210" Larrowe <https://github.com/JL2210>
 - Maja Kądziołka <github@compilercrim.es>
-- The Musl C library <http://www.musl-libc.org>
+- The Musl C library <https://musl.libc.org/>
 - obskyr <powpowd@gmail.com>
 - The OpenBSD Project <http://www.openbsd.org>
 - Quint Guvernator <quint@guvernator.net>
diff --git a/README.md b/README.md
index a74652c0..dd8dfa84 100644
--- a/README.md
+++ b/README.md
@@ -136,7 +136,7 @@ The RGBDS source code file structure is as follows:
 ## 4. Acknowledgements
 
 RGBGFX generates palettes using algorithms found in the paper
-["Algorithms for the Pagination Problem, a Bin Packing with Overlapping Items"](http://arxiv.org/abs/1605.00558)
+["Algorithms for the Pagination Problem, a Bin Packing with Overlapping Items"](https://arxiv.org/abs/1605.00558)
 ([GitHub](https://github.com/pagination-problem/pagination), MIT license),
 by Aristide Grange, Imed Kacem, and Sébastien Martin.
 
diff --git a/src/gfx/pal_packing.cpp b/src/gfx/pal_packing.cpp
index cdf0e3c8..277aec9f 100644
--- a/src/gfx/pal_packing.cpp
+++ b/src/gfx/pal_packing.cpp
@@ -25,7 +25,7 @@ using std::swap;
 
 namespace packing {
 
-// The solvers here are picked from the paper at http://arxiv.org/abs/1605.00558:
+// The solvers here are picked from the paper at https://arxiv.org/abs/1605.00558:
 // "Algorithms for the Pagination Problem, a Bin Packing with Overlapping Items"
 // Their formulation of the problem consists in packing "tiles" into "pages"; here is a
 // correspondence table for our application of it:
diff --git a/src/gfx/pal_spec.cpp b/src/gfx/pal_spec.cpp
index 2ff18a65..3442a958 100644
--- a/src/gfx/pal_spec.cpp
+++ b/src/gfx/pal_spec.cpp
@@ -463,7 +463,6 @@ static void parseACTFile(std::filebuf &file) {
 
 static void parseACOFile(std::filebuf &file) {
 	// https://www.adobe.com/devnet-apps/photoshop/fileformatashtml/#50577411_pgfId-1055819
-	// http://www.nomodes.com/aco.html
 
 	char buf[10];