There are 5 titles associated with this firm.

Richardson, Caroline E. Poems, By Mrs. G. G. Richardson, Dumfries. Edinburgh: Robert Cadell and Co. [41 St. Andrew Street], Simpkin, Marshall and Co., William Crofts, 1828.
Richardson, Caroline E. Poems, By Mrs. G. G. Richardson, Dumfries. Second edition. Edinburgh: Robert Cadell and Co. [41 St. Andrew Street], Simpkin, Marshall and Co., William Crofts, 1828.
Richardson, Caroline E. Poems. By Mrs. G. G. Richardson, Dumfries. Edinburgh: Robert Cadell and Co. [41 St. Andrew Street], Simpkin, Marshall and Co., John Sinclair, 1828.
Corbett, Marion, and Margaret Corbett. Tales and Legends. By the authors of "The Odd Volume," &c. In three volumes. Edinburgh: W. Simpkin and R. Marshall, Robert Cadell and Co. [41 St. Andrew Street], 1828.
Richardson, Caroline E. Poems. By Mrs. G. G. Richardson, Dumfries. Edinburgh: Robert Cadell and Co. [41 St. Andrew Street], Simpkin, Marshall and Co., John Sinclair, 1829.