1 Reference in a will to another document without which the will cannot be understood (the document then forms part of the will). For example, a will leaving a specified sum “to each of the persons listed in my notebook” incorporates the notebook. The document must be clearly identified in the will, in existence at the date of the will, and clearly referred to as being in existence at that date.
2 Reference to named contract terms, for example on the back of a railway ticket, saying where the terms can be seen for those who want to read them. This will often be sufficient to incorporate the terms by reference into the contract, although the other party may not have taken the opportunity to read the terms. However, there are risks in incorporation; for example, it is harder to enforce an exclusion of liability clause (see exemption clause) if the terms are merely incorporated by reference.