Singfat C-C-L (1998). “Bidding Efficiencies for Rights to Car Ownership in Singapore.” Omega 26(2): 297-306.

Simar L and PW Wilson (2007). “Estimation and Inference in Two-Stage, Semi-Parametric Models of Production Processes.” J Econometrics 136(1): 31-64.

Simar L and V Zelenyuk (2006). “On Testing Equality of Distributions of Technical Efficiency Scores.” Econometric Reviews 25(4): 497-522.

Simar Lo and P Wilson (2001). “Testing Restrictions in Nonparametric Efficiency Models.” Communications in Statistics: Simulation and Computation 30(1): 159.

Simar Lo and PW Wilson (2000). “A General Methodology for Bootstrapping in Non-Parametric Frontier Models.” J Applied Statistics 27(6): 779-802.

Simons R (1996). “How DEA Can Be a Spur to Improved Performance.” Operations Research Newsletter : 11-13.

Simper R and LM Drake (2001). “The Economic Evaluation of Policing Activity: An Application of a Hybrid Methodology.” European J Law and Economics 12.

Simpson G (2005). “Programmatic Efficiency Comparisons between Unequally Sized Groups of DMUs in DEA.” JORS 56(12): 1431-1438.

Silkman RH (1986). Measuring Efficiency: An Assessment of Data Envelopment Analysis. San Francisco, USA, Jossey-Bass.

Silva EG and JD Costa (2006). “Are Voters Rationally Ignorant? An Empirical Study of Portuguese Local Elections.” PORT ECON J 5(1): 31-44.