Well, here is a list of books with information about foxes and stories featuring them.

"known" Books
These books are well known among fox-enthusiasts (because there so good) 
"Running with the Fox" by David MacDonald 
"How to spot a fox" by J.David Henry 
   Chapters Pub. Ltd, Shelburn, Veront 05482
   ISBN 1-881527-18-2 (hardcover): $21.95
   ISBN 1-881527-17-4 (softcover) : $12.95 
"The catlike canine" by J.David Henry 
"Foxes: living on the edge".   J. David Henry. 
Vulpina: The Story of a Fox
    by David MacDonald
    Published in Great Britain, 1977.  ISBN 0-00-195229-3. 
 "The Desert Fox Family Book"
 Published by North/South Books Written by Hans Gerold Laukel
 A book about Fennec-foxes. Shall be 'a little basic' but with wonderful photos 
"Country Foxes" by Hugh Kolb and illustrated by Diana Brown.
 The book can be obtained from the publisher for GBP 7.99 + GBP 1.50 post and packing ( he accepts visa & mastercard). 
 The address is Whittet Books Ltd 
                       18 Anley Road 
                       London W14 0BY
 "The World of the Fox", by Rebecca L. Grambo,
1995. Sierra Club Books,
ISBN 0-87156-377-0. $25.00 (US dollars)
Hardcover, lots of good illustrations.
"On the Trail of the Fox", by Claudia Schnieper; Photographs by Felix Labhardt
A Carlrhoda Nature Watch Book
Carolrhoda Books, Minneapolis, 1986
Original Edition published 1985 by Kinderbuchverlag KBV,
  Lucerne, Switzerland as "Dem Fuchs auf der Spur"
"Describes the habits of the red fox, including its birth,
mating, raising of young, hunting, fighting, and playing."
48 pages. 
"Fox" by Caroline Arnold; Photographs by Richard Hewett
Morrow Junior Books, New York, 1996
While briefly giving notes on many fox species, the bulk
of the book and photos cover the life and habits of
Kit Foxes. 48 pages. 
"The Foxes" by Mark E. Ahlstrom
Baker Street Productions, Mankato, MN, 1983
Nice photos of various species. 48 pages. 
"Foxes" by Kay McDearmon
A Skylight Book -- Dodd, Mead & Co., New York, 1981
61 pages. Expressive B&W photos of different kinds of
"Wonders of Foxes" by Sigmund A. Lavine
Dodd, Mead, & Co., New York, 1986
B&W photos of different fox species. 80 pages. 
"Red Fox" by Merebeth Switzer
Grolier Limited, 1986
Excellent, beautifully colored photos of the best-known
species of fox. Good close-ups. 48 pages. 
biological sources
Jia, J. & Ma, J. 1989. Preliminary study on the fluctuations 
           in the yearly numerical tendency of the red fox in 
           Heilongjiang, China. - ZOOLOGICAL RESEARCH 10(3):200-206
           (in Chinese with English Abstract).
 Jia, J. 1989. Conservation of the threatened wildlife in China.
           - INFORMATION & STRATEGY, YICHUN, CHINA (in Chinese).
Ma, J. & Jia, J. 1990. Wildlife Management. - NFU PRESS
           (in Chinese with English Contents), 320 pp.
           ISBN 7-81008-087-3/Q.6
Jia, J. & Xiao, Q. 1990. Study on the winter home range of the red foxes in the west suburbs of Harbin. - 
ACTA THERIOLOGICA SINICA 10(4):268-275 (in Chinese with English Abstract).
Jia, J. 1991. The trail identifications of red fox, racoon dog     and badger in the wild. -
CHINESE WILDLIFE 61(3):18-21   (in Chinese).
 Jia, J., Xiao, Q., Xu, L. & Ma, H. 1991. A primary observation of the red fox dens. - 
ACTA THERIOLOGICA SINICA 11(4):266-269 (in Chinese with English Abstract).
 Jia, J. & Ma, J. 1992. Principal component analysis on the dens of red fox in the western suburbs of Harbin. - 
JOURNAL OF NORTHEAST FORESTRY UNIVERSITY 20(1):22-29 (in Chinese with English Abstract).
Dag Frommhold: "Keine Gnade fuer Fuechse", 360 S., Windeck 1996.
DM 24,80 from:
Okapi Verlag, Im Hahmich 1, 51570 Windeck-Saal. (Germany) 
"Reynard, The Story of a Fox returned to the wild" by Alice Mills Leighner
Atheneum, New York, 1986
The story of a lost fox cub, mistaken for an abandoned
puppy, and how he was raised to be returned to the wild
by the dedicated volunteers at a wildlife rehab center.
Lots of winning B&W photos of Reynard growing up at the
shelter and interacting with his human handlers. 48 pages. 
(This can be very interesting 'cause you can get known how different people in different times and continents thought of the fox) 
"The Most Delectable History of Reynard the Fox" edited by Joseph Jacobs, 
and published in 1967 by Schoken Books, New York. It has illustrations by W. Frank Calderon. 
"The History of Reynard the Fox" printed by Harvard University Press in 1960. It reprints the translated version by William Caxton in 1481, and includes some woodcut illustrations 
(online) Libraies
Amazon.com Give it a try, they have everything 
NHBS BookNet (natural history book store)