1. https://ai.googleblog.com/2021/11/model-ensembles-are-faster-than-you.html
2. Wang X, Kondratyuk D, Christiansen E, Kitani KM, Alon Y, Eban E. Wisdom of Committees: An Overlooked Approach To Faster and More Accurate Models. arXiv [cs.CV]. 2020. Available: http://arxiv.org/abs/2012.01988
Wang et al shows that ensembles are not more resource demanding than big models with similar performance in CV tasks.