Prague C.N. Programming with R: BASE for DOS / C.N.Prague,J.E.Hammitt,A.P.Thompson, 1989. - XII,496 p. p. - Текст : непосредственный.
Prague C.N. dBASE III plus programming : Tips and techniques / C.N.Prague,J.E.Hammitt, 1986. - XI,305 p. p. - Текст : непосредственный.