Suggest how an engineer responsible for drawing up a system requirements specification might keep track of the relationships between functional and non-functional requirements.

One method to track the relationships between functional and non-functional requirements may include a type of flowchart. This chart could go from one functional requirement to the next logical functional requirement with the ability to branch off if there are other similar requirements. The non-functional requirements could then be written next to which ever functional requirement they are related to. The non-functional requirements may be repeated if they relate to multiple functional requirements.