Hesser, Dale T. Focus on Earth Science / Dale T. Hesser and Susan S. Leach - Ohio : Merrill, c1989. - x, 61 p. : ill. ; 25 cm. Includes index. ISBN: 0675026717 LCCN: Subjects--Topical Terms: GeologyPeriodicals LC Class. No.: QE1 / .E13 1989 Dewey Class. No.: 550.5 / H583f