Memoirs of the American Mathematical Society, ISSN 0065-9266 ; Volume 93, Number 452
Print version: Thomson, Brian S., 1941- Derivates of interval functions. Providence, Rhode Island : American Mathematical Society, c1991 96 pages Memoirs of the American Mathematical Society ; Volume 93, Number 452. ISBN 9780821825037
"September 1991, Volume 93, Number 452 (first of 3 numbers)."