Measurement of Serum Testosterone in Nondiabetic Young Obese Men: Comparison of Direct Immunoassay to Liquid Chromatography-Tandem Mass Spectrometry oleh Ana Martínez-Escribano, Julia Maroto-García, Maximiliano Ruiz-Galdón, Rocío Barrios-Rodríguez, Juan J. Álvarez-Millán, Pablo Cabezas-Sánchez, Isaac Plaza-Andrades, María Molina-Vega, Francisco J. Tinahones, María Isabel Queipo-Ortuño, José Carlos Fernández-García