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I am using apacite package to cite in my code, but it doesn't work. They show question marks when I run it. Here's the .tex and .bib.
\documentclass[a4paper,12pt]{article}
\usepackage{apacite}
\usepackage{pbox}
\usepackage{longtable}
\usepackage[a4paper]{geometry}
\geometry{a4paper,tmargin=2.0cm ...