ZHANG, Gexiang et al. QEAM: An Approximate Algorithm Using P Systems with Active Membranes. INTERNATIONAL JOURNAL OF COMPUTERS COMMUNICATIONS & CONTROL, [S.l.], v. 10, n. 2, p. 263-279, apr. 2015. ISSN 1841-9844. Available at: <http://univagora.ro/jour/index.php/ijccc/article/view/1757>. Date accessed: 27 june 2022.