Josef B. Baker Alan P. Sexton Volker Sorge MaxTract: Converting PDF to $\mbox\LaTeX$ , MathML and Text. 422-426 2012 AISC/MKM/Calculemus https://doi.org/10.1007/978-3-642-31374-5_29 conf/aisc/2012 db/conf/aisc/aisc2012.html#BakerSS12