diff --git a/DSP.md b/DSP.md
index bd37129..2404d34 100644
--- a/DSP.md
+++ b/DSP.md
@@ -46,12 +46,12 @@ Consider the high-frequency sine wave in red.
 If the signal is sampled every integer, its unique reconstruction is the signal in blue, which has completely different harmonic content as the original signal.
 If correctly bandlimited, the original signal would be zero (silence), and thus the reconstruction would be zero.
 
-[![](https://upload.wikimedia.org/wikipedia/commons/thumb/2/28/AliasingSines.svg/640px-AliasingSines.svg.png)](https://en.wikipedia.org/wiki/File:AliasingSines.svg)
+[![](https://upload.wikimedia.org/wikipedia/commons/2/28/AliasingSines.svg)](https://en.wikipedia.org/wiki/File:AliasingSines.svg)
 
 A square wave has harmonic amplitudes $\frac{1}{k}$ for odd harmonics $k$.
 However, after bandlimiting, all harmonics above $f_{sr}/2$ become zero, so its reconstruction should look like this.
 
-[![](https://upload.wikimedia.org/wikipedia/commons/thumb/b/b3/Gibbs_phenomenon_50.svg/640px-Gibbs_phenomenon_50.svg.png)](https://en.wikipedia.org/wiki/File:AliasingSines.svg)
+[![](https://upload.wikimedia.org/wikipedia/commons/b/b3/Gibbs_phenomenon_50.svg)](https://en.wikipedia.org/wiki/File:Gibbs_phenomenon_50.svg)
 
 The curve produced by a bandlimited discontinuity is known as the [Gibbs phenomenon](https://en.wikipedia.org/wiki/Gibbs_phenomenon).
 A DSP algorithm attempting to model a jump found in sawtooth or square waves must include this effect, such as by inserting a minBLEP or polyBLEP signal for each discontinuity.
@@ -78,7 +78,7 @@ The filter is "linear" because the filtered sum of two signals is equal to the s
 
 A log-log plot of $H(i \omega)$ is called a [Bode plot](https://en.wikipedia.org/wiki/Bode_plot).
 
-[![](https://upload.wikimedia.org/wikipedia/commons/thumb/6/60/Butterworth_response.svg/640px-Butterworth_response.svg.png)](https://en.wikipedia.org/wiki/File:Butterworth_response.svg)
+[![](https://upload.wikimedia.org/wikipedia/commons/6/60/Butterworth_response.svg)](https://en.wikipedia.org/wiki/File:Butterworth_response.svg)
 
 To be able to exploit various mathematical tools, the transfer function is often written as a rational function in terms of $s^{-1}$
 $$H(s) = \frac{\sum_{p=0}^P b_p s^{-p}}{\sum_{q=0}^Q a_q s^{-q}}$$
diff --git a/Makefile b/Makefile
index d4049fa..26a924b 100644
--- a/Makefile
+++ b/Makefile
@@ -2,7 +2,7 @@
 build:
 	gitbook build
 
-all: build pdf
+all: build
 
 run:
 	gitbook serve --port 8080