When the goods are contingent and a market maker is used to construct the price formation process there is a line of work stemming from https://arxiv.org/abs/1003.0034 on this  ( http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.296.6481&rep=rep1&type=pdf , https://papers.nips.cc/paper/4529-interpreting-prediction-markets-a-stochastic-approach.pdf )