Phenolic content and antioxidant action in needle extracts from Pinus cooperi, P. durangensis, P. engelmanii and P. teocote Tekijät: Sáenz-Esqueda, María de los Ángeles, Rosales-Castro, Martha, Rocha-Guzmán, Nuria Elizabeth, Gallegos-Infante, José Alberto, González-Laredo, Rubén Francisco