Kei Uchizawa Takao Nishizeki Eiji Takimoto Size and Energy of Threshold Circuits Computing Mod Functions. 724-735 2009 MFCS http://dx.doi.org/10.1007/978-3-642-03816-7_61 conf/mfcs/2009 db/conf/mfcs/mfcs2009.html#UchizawaNT09