Vladimir Pervouchine Graham Leedham Study of structural features of handwritten grapheme ‘th’ for writer identification. 417-422 2007 IAS http://doi.ieeecomputersociety.org/10.1109/IAS.2007.81 conf/IEEEias/2007 db/conf/IEEEias/IEEEias2007.html#PervouchineL07