Nitrogen balance in preterm infants fed formula enriched with long chain folyunsathurated fatty acids - Martinez, F E; Santos, M M; Sieber, V M; Ferlin, Maria Lúcia Silveira; Mussi-Pinhata, Marisa Márcia; Gonçalves, Arthur Lopes; Jorge, S M (Aocs Conference on Pufa in Infant Nutrition, 1996)