A smooth stone from the brook : Or, an humble attempt to prevent backsliding from the principles of the covenanted Church of Scotland, in some letters to the Rev. George Lawson, by the Reverend William Willis. - Willis, William (printed for the author, and sold by M. Ogle - J. Ogle, Edinburgh - J. Fowler, Paisley - G. Laird, Greenock, 1799)