Lipid Profiles of Human Brain Tumors Obtained by High-Resolution Negative Mode Ambient Mass Spectrometry oleh Denis S. Zavorotnyuk, Stanislav I. Pekov, Anatoly A. Sorokin, Denis S. Bormotov, Nikita Levin, Evgeny Zhvansky, Savva Semenov, Polina Strelnikova, Konstantin V. Bocharov, Alexander Vorobiev, Alexey Kononikhin, Vsevolod Shurkhay, Eugene N. Nikolaev, Igor A. Popov