There are 2 titles associated with this person.

Stevens, Grace B. Llewellen, or The vale of Phlinlimmon: a novel. In two volumes. Philadelphia: M. Carey and Son [126 Chestnut Street], 1818.
Stevens, Grace B. Llewellen, or, The Vale of Phlinlimmon: A Novel. In Three Volumes. Edinburgh: Macredie, Skelly, and Co., Thomas and George Underwood, 1818.