Kirillov Sergej Aleksandrovič: Norm estimates of functions in Lorentz spaces. In: Acta scientiarum mathematicarum, (65) 1-2. pp. 189-201. (1999)
Kirillov Sergej Aleksandrovič: Some estimates for orthonormal systems from BMO. In: Acta scientiarum mathematicarum, (64) 1-2. pp. 223-230. (1998)