1. Atkins PW, Symonds MCR (1967) The structure of inorganic radicals. An application of electron spin resonance to the study of molecular structure. Elsevier, Amsterdam London New York
2. Bagmut NN, Bespalko NA, Brick AB, Matyash IV, Fedotov YuV (1975) EPR of the NH+ 3 ion-radical in feldspars (in Russian). Geokhimiya 10:1568?1571
3. Carrington A, McLachlan AD (1967) Introduction to magnetic resonance with application to chemistry and chemical physics. Harper and Row, New York Evanston London
4. Erd RC, White DE, Fahey JJ, Lee DE (1964) Buddingtonite ? ammonium feldspar with zeolitic water. Am Mineral 49:831?850
5. Marfunin AS, Bershov LV (1970) Paramagnetic centers in feldspar and their possible crystallochemical and petrological significance (in Russian). Dokl Akad Nauk SSSR 193:412?414 English translation: Dokl Acad Sci Earth Sci USSR 193:129?131