Energy crops cultivated on the slag from incineration of the sewage sludge energy value assessmentAnna Głowacka, Krzysztof Tarnowski, Sławomira Bering, Jacek Mazur, Justyna Kiper and Czesław WołoszykE3S Web Conf., 22 (2017) 00055DOI: https://doi.org/10.1051/e3sconf/20172200055