Spent coffee grounds improve the nutritional value in elements of lettuce (Lactuca sativa L.) and are an ecological alternative to inorganic fertilizers

1. Cervera-Mata, A.
2. Navarro-Alarcón, M.
3. Delgado, G.
4. Pastoriza, S.
5. Montilla-Gómez, J.
6. Llopis, J.
7. Sánchez-González, C.
8. Rufián-Henares, J.Á.