馬糞證券 says to 電訊台 https://www.amazon.com/Discrete-Mathematics-Its-Applications-Seventh/dp/0073383090/ref=pd_lpo_14_t_2/145-4955650-3586005?_encoding=UTF8&pd_rd_i=0073383090&pd_rd_r=4481da5e-9bf5-4351-9de2-4f2ae977cbbc&pd_rd_w=bEIeS&pd_rd_wg=DfgSc&pf_rd_p=7b36d496-f366-4631-94d3-61b87b52511b&pf_rd_r=NTGRMMSKSVDQ2ETYYNAG&psc=1&refRID=NTGRMMSKSVDQ2ETYYNAG