Due to growing interest to decision support systems in Russia, several models for business processes formalization have been developed in recent years. Authors offered their own model, which is described at the end, after research of existing models and identification of their drawbacks. The paper presents analysis of models that are available in Russia for business processes formalization. Some of these models were developed in frames of certain research and were not implemented, others became a basis for software. Authors are also finishing work on the decision support system BPsim.DSS that is based on self-developed multi-agent resource conversion processes apparatus and takes into account all found drawbacks of existing models. Paper focuses on theoretical aspects, though information on the system may be found by contacting the authors.