A.  Bevilacqua, Sandner, C., Gerosa, A., and Neviani, A., ?Quadrature VCOs Based on Coupled PLLs?, in IEEE International Symposium on Circuits and Systems, 2007. ISCAS 2007, 2007, pp. 2140 -2143.

A.  Bevilacqua, Pavan, F. P., Sandner, C., Gerosa, A., and Neviani, A., ?Transformer-Based Dual-Mode Voltage-Controlled Oscillators?, IEEE Transactions on Circuits and Systems II: Express Briefs, vol. 54, pp. 293 -297, 2007.