Chicago: Robert Stawell Ball, "Preface," Great Astronomers, ed. Smiles, Samuel, 1812-1904 in Great Astronomers Original Sources, accessed May 4, 2024, http://www.originalsources.com/Document.aspx?DocID=RFCS7NDDTYQAQ9E.
MLA: Ball, Robert Stawell. "Preface." Great Astronomers, edited by Smiles, Samuel, 1812-1904, in Great Astronomers, Original Sources. 4 May. 2024. http://www.originalsources.com/Document.aspx?DocID=RFCS7NDDTYQAQ9E.
Harvard: Ball, RS, 'Preface' in Great Astronomers, ed. . cited in , Great Astronomers. Original Sources, retrieved 4 May 2024, from http://www.originalsources.com/Document.aspx?DocID=RFCS7NDDTYQAQ9E.