Conventional and twin row spacing in different population densities for maize (Zea mays L.) - Balem, Zenilson; Modolo, Alcir José; Trezzi, Michelangelo Muzzel; Vargas, Thiago de Oliveira; Baesso, Murilo Mesquita; Brandelero, Evandro Martin; Trogello, Emerson (African Journal of Agricultural Research, 2014)