In order to work with identification problems and to provide them as input to identification algorithms, we also need to represent such problems in files, and it is highly desirable that an entire problem can be represented in a single file. Since an identification problem is an optimization problem and not a model, common model formats such as SBML are not applicable, and no existing format known to us can be used for this purpose. However, the output of an identification algorithm is a model and can be represented in SBML. Also, if a partially known initial model is available in SBML, an identification algorithm can input that part in SBML and the rest of the identification problem in our format.