A comparative study of digital ΣΔ modulators for fractional-N synthesis. - Keliu Shu; Edgar Sánchez-Sinencio; Franco Maloberti; Udaykiran Eduri (ICECS, 2001)

A 5-GHz prescaler using improved phase switching. - Keliu Shu; Edgar Sánchez-Sinencio (ISCAS (3), 2002)

A 2.1-GHz monolithic frequency synthesizer with robust phase switching prescaler and loop capacitance scaling. - Keliu Shu; Edgar Sánchez-Sinencio; José Silva-Martínez (ISCAS (4), 2002)

A 2.4-GHz monolithic fractional-N frequency synthesizer with robust phase-switching prescaler and loop capacitance multiplier. - Keliu Shu; Edgar Sánchez-Sinencio; José Silva-Martínez; Sherif H. K. Embabi (IEEE J. Solid State Circuits, 2003)