Collaboration is key to implementing continuity of care. In Estonia, the key aspects of healthcare provider obligations and their movement inside clinical processes are defined in the Law of Obligations Act. We have analyzed and annotated these aspects with the standard ISO 13940 System of Concepts to Support Continuity of Care (ContSys) to integrate the legal domain into a holistic model. The aim is to integrate legal domain knowledge within an interoperability and integration framework in further work. For this, we first need to explicate a principled method based on semantic annotation. Our results show that the Law of Obligations Act has a high concept coverage of the ContSys, indicating it is appropriate for further modeling and integrating the legal domain. Further work will model the collaborative perspective of the clinical process to allow modeling of the distribution of responsibilities between multi-stakeholder roles participating in coordinated continuity of care. We deem ContSys appropriate for national and global implementation, as its system of concepts underpins, e.g., the ISO International Patient Summary. A review found that ContSys has been aligned with data exchange standards and an upper ontology, but to the best of our knowledge, not with the legal domain.