Arnold, Virginia A. Friends Aloft / Virginia A. Arnold u.a. ; Forward by Joan I. Glazer, Margaret H. Lippert. - London ; New York : Collier Macmillan Publ. : Macmillan Publ. Co. , 1989. - 344 p. - Macmillan Reading Program Level 7 . ISBN: 0-02-174830-6 Subjects--Topical Terms: English language