Some books in the library on iconography and symbolism that may help you:

Illuminated Manuscripts

CALL #      ND2889 .B76 1994
AUTHOR    Brown, Michelle
TITLE        Understanding Illuminated Manuscripts: A Guide to Technical Terms

Christian Art/Apostles, Saints

CALL #      N8080 .K25
AUTHOR    Kaftal, George
TITLE        Iconography of the saints in Tuscan painting

CALL #      N7830 .S3513
AUTHOR    Schiller, Gertrud
TITLE        Iconography of Christian art

Religious Art/General Works

CALL #      N7830 .M87 1996
AUTHOR    Murray, Peter
TITLE        The Oxford companion to Christian art and architecture

Symbolism. Emblematic Art/Dictionaries

CALL #      N7825 .S68 1994
AUTHOR    Speake, Jennifer
TITLE        The Dent dictionary of symbols in Christian art

CALL #      N7560 .H34 2008
AUTHOR    Hall, James
TITLE        Dictionary of subjects and symbols in art

Symbolism. Emblematic Art/General Works

CALL #       N7830 .F37
AUTHOR     Ferguson, George Wells
TITLE         Signs & symbols in Christian art

Humanities/Philosophy, Theory

CALL #      AZ108 .T74 2005
TITLE        The complete dictionary of symbols

Occult Sciences/Magic, Hermetics, Necromancy

CALL #       BF1623 .S9 C513
AUTHOR     Cirlot, Juan Eduardo
TITLE         A dictionary of symbols

Christianity

CALL #       BR95 .M396 1983
AUTHOR     Metford, J. C. J.
TITLE         Dictionary of Christian lore and legend

Biblical Criticism and Interpretation

CALL #       BS513.2 .D8313 1994
AUTHOR     Duchet-Suchaux, Gaston
TITLE         The Bible and the saints

Practical Theology – Worship/Christian Symbols and Symbolism

CALL #       BV150 .A66 1994
AUTHOR       Apostolos-Cappadona, Diane
TITLE        Dictionary of Christian art

CALL #       BV150 .W4 1938
AUTHOR     Webber, F. R. (Frederick Roth)
TITLE         Church symbolism; an explanation of the more important symbols of
                 the Old and New Testament, the primitive, the mediaeval and the
                 modern church

Other helpful texts are available.