7InftyProjeet. Infty reader version 2.5 [ EB/OL]. http://www, inftyproject, org/.
8Yang M, Fateman R. Extracting mathematical expressions from postscript documents [ C ]. Proceedings of the International Symposium on Symbolic and Algebraic Computation. Santander, 2004 : 305 - 311.
9Adobe Systems Incorporated. Postscript Language Reference, Third Edition [ M]. Massachusetts: Addison-Wesley Publishing Company, 1999.