References (1974). The non-linear two-stage least squares estimator. Journal of Econometrics, 2: 105–110. , , , and (2012). Sparse models and methods for optimal instrument with an application to eminent domain. Econometrica, 80(6): 2369–2429. and (2013). Least squares after model selection in high-dimensional sparse models. Bernoulli, 19(2): 521–547. , , , and (2017). Program evaluation and causal inference with high dimensional data. Econometrica, 85(1): 233–298. , , and (2014).
