prism: Fix pdf export

prism/benchmark.org

 #+TITLE: PRISM Benchmarks
+#+LATEX_HEADER: \usepackage[a4paper,margin=1in,landscape]{geometry}
 
 * Introduction
 
@@ -1190,7 +1191,7 @@
    We consider the scenario where two stations trying to send packets simultaneously.
 
    The PRISM model is taken from [KNS02a] using the integer semantics given in [KNS06]. In the model one time unit
-   corresponds to 50μs and to ensure integer bounds, where neccessary, scaling lower bound constraints down and
+   corresponds to 50\mu s and to ensure integer bounds, where neccessary, scaling lower bound constraints down and
    upper bound constraints up to sensure a sound abstraction.
 
    For more information on the probabilistic timed automata see: http://www.prismmodelchecker.org/casestudies/wlan.php