Chrun, Antonio Sergio, et al. “Influence of the Aerial <i>burrknot< i> Galls on the Initial Development of the Apple Plants”. Pesquisa Agropecuaria Brasileira, vol. 27, no. 3, Mar. 1992, pp. 509-12, doi:10.1590/S1678-3921.pab1992.v27.3675.