If ALPS contributes to published research, cite the latest framework paper below and any method-specific paper relevant to the application you used.
B. Bauer et al., “The ALPS project release 2.0: Open source software for strongly correlated systems,” Journal of Statistical Mechanics: Theory and Experiment 2011, P05001 (2011). doi:10.1088/1742-5468/2011/05/P05001
The maintained list of implementation and algorithm papers for individual ALPS applications is available on the ALPS documentation website.