Siswono, H., W. Wartono, and S. Koes H. “PENGARUH PROBLEM BASED LEARNING BERBANTUAN VIRTUAL LABORATORY TERHADAP KETRAMPILAN PROSES SAINS DAN PENGUASAAN KONSEP SISWA DI SMA”. PROSIDING SEMINAR NASIONAL FISIKA (E-JOURNAL), Vol. 3, Oct. 2014, pp. 22 -6, https://journal.unj.ac.id/unj/index.php/prosidingsnf/article/view/5435.