Since I've gotten a lot of e-mails and such asking about what references and/or media I use for my work, I thought I'd take some time to write it all down. So here we go...

Prismacolor Verithin Colored Pencils (fine lines, hard lead)
Prismacolor Colored Pencils (thicker lead, somewhat soft)
Prang Colored Pencils
General Graphite Drawing Pencils (various types)
General Chalk Pencils
Savoir Faire Gouache (assorted colors)
Miscellaneous erasers
Prismacolor Colored Marker Pens
Prismacolor Premier Fineline Pens (005, 01, 03, 05, 08 sizes)
Prismacolor Premier Pen Asst. (brush, chisel-tip, 005, 01, 05)
Staedtler Pigment Liner (01, 03, 05, 07 sizes)
Assorted technical/drafting pens
Various templates (circles, ovals, ellipses)
Various rulers
Various French Curve sets
Protractor
Ticonderoga Erasable Carmine Red Pencils
Various watercolors and acrylic paints, as needed

And here are the books I use for learning new techniques or for additional reference:

Art Simplified by Pedro J. Lemos and John T. Lemos (this book was "published" in the early 1900's; it was done in a way that allows pages to be added to the book as necessary. All the men are wearing turn-of-the-century style clothing or bowler hats, the only car shown in the book is a very early 19-teens racing car, etc.)

Colored Pencil Step By Step - Walter Foster Art Series, 2003 (details colored pencil techniques)

The Encyclopedia of Colored Pencil Techniques by Judy Martin, 1992 (details techniques for getting effects with colored pencils)

An Introduction to Art Techniques - The Dorling Kindersley Art School, 1995 (covers numerous techniques for all kinds of traditional media)

How To Sketch by various artists, 1954, 1960 (self-explanatory. A quick how-to book for getting forms down to their basic shapes)

Graphics For Designers by Robert R. Hartmann, 1976, 1978 (covers perspectives, lighting and shading; primarily covers home/product design)

Drawing Realistic Textures in Pencil by J.D. Hillberry, 1999 (the title says it all)

How to Draw Cars Like a Pro by Thom Taylor, 1996 (mostly cartooning stuff, but gives tips on perspective and reflective highlighting techniques)

Cat Musculature: A Photographic Atlas by Gordon M. Greenblatt, 1980 (a photographic reference of the musculature and skeletal system of the domesticated feline-useful for understanding how their claws, tails and spines work)

Landmarks and Surface Markings of the Human Body by L. Bathe Rawling, 1920 (covers veins, tendons, and other surface markings of the body, as well as details the weight of various organs)

Atlas of Human Anatomy for the Artist by Stephen Rogers Peck, 1951/1979 (covers the human form in shapes, plus full detail on skeletal and muscular systems. Also includes details about skin, hair, facial features, differences in body types, races, ages, and expressions)

ABC's of the Human Body - Reader's Digest Hardcover, 1987 (details information about the body, and explains the hows and whys of the body's habits and abilities)

The HarperCollins Illustrated Medical Dictionary - various doctors, 1985 (covers ailments of the body, as well as damage caused by injury. Excellent illustrations of musculature, ligaments, tendons and both skeletal and nervous systems)

There are also numerous books I have on airbrushing, animation, cartooning and comic strip designing, but those listed above can be used in most any art situation. A lot of the books I have not actually read; I use them for reference or insight (for example, to figure out how to layer colors a certain way for an effect). It's often easier to consult the books than to putz around with the drawing supplies trying to figure it out. Several of these books probably cannot even be found nowadays, and their prices range from about 10 bucks to over 60 dollars. Now we know where the term "starving artist" comes from! The supplies and reference materials cost so damn much, you almost go bankrupt trying to learn the skill!

While I do not use photos for reference in either my anthro or mainstream work (unless it is a specific location or subject), I do have several manilla folders full of photos and reference sheets about things such as aircraft, weapons, buildings, people (cultures and costumes), animals (including in-depth information), outer space shots/planets, vehicles, furniture, etcetera. It's always good to have a collection of reference material to fall back on. This way, if someone says "Oh, can you draw a 1937 Cord?" you can say "I sure can" without batting an eye, even if you have no idea what a 1937 Cord looks like. The customer doesn't need to know that!

So there you go. Hope that was informative enough for you...