PHILIPOWSKI, J. F.; DEDECEK, R. A.; MEDRADO, M. J. S. Influence of different winter soil cover plants and soil tillage systems on erva-mate (Ilex paraguariensis St. Hil.) productivity, in Ponta Grossa,PR. Pesquisa Florestal Brasileira, n. 48, p. 3–13, 30 Jun.2004.