EPR and Quantum Chemical Studies of the pH-sensitive Imidazoline and Imidazolidine Nitroxides with Bulky Substituents. - Bobko AA; Kirilyuk IA; Gritsan NP; Polovyanenko DN; Grigor'ev IA; Khramtsov VV; Bagryanskaya EG (Applied magnetic resonance, 2010)