Laws Relating to Inheritance of Account Books (Tablets),  Digest of Justinian

59. Julianus, Digest, Book XXXIV.

Where anyone bequeaths a promissory note, it is understood that he had in mind not only the tablets upon which it is written, but also the rights of action, the proof of which is contained in the tablets. For it is clear that we use the same "note" instead of the said rights of action; so when the note is sold, we understand that the claim was also disposed of. Moreover, where anyone bequeaths a claim, he is understood to have bequeathed what can be recovered by an action at law.

88. Scævola, Opinions, Book III.

. . . The father had kept, in the name of one of his sons, an account book of debts, and it was afterwards decided and held that what remained in said book in the name of his son was due to the latter; but not what had been already collected and placed by his father among the assets of his estate.