04 - Physical medium
a - Paper
b - Wood
c - Stone
d - Metal
e - Synthetic
Man-made substances other than
textiles, plastic, and vinyl.
f - Skin
Excludes leather, parchment, and
vellum.
g - Textile
i - Plastic
l - Vinyl
n - Vellum
Fine-grained unsplit lambskin, kidskin, or calfskin
prepared especially for writing or drawing on.
p - Plaster
u - Unknown
v - Leather
w - Parchment
Skin of a sheep or goat prepared for writing on.
z - Other
| - No attempt to code