This paper investigates the performance of uplink massive multiple-input multiple-output (MIMO) systems with low-resolution analog-to-digital converters (ADCs) operating over Rician fading channels. We study zero-forcing (ZF) group successive interference cancellation (GSIC) receivers, which cover the ZF and ZF-SIC receivers as two special cases. The spectrum efficiency (SE) is analyzed for general power allocation under both perfect and imperfect channel state information (CSI). We further derive the optimal power allocation for a given quality-of-service (QoS) for the GSIC receivers. Based on random matrix theory, the corresponding asymptotic approximations of the signal-to-interference-plus-noise-ratio (SINR) for the system and the power allocation are derived for both perfect and imperfect CSI. The derived approximations are verified and shown highly accurate, providing fast characterization of the performance and near-optimal resource allocation for different system parameters. Th