Finding Formulas for Heat Capacity

[Vivamus]

Homework Statement

I'm needing to write a program for thermodynamics, but before I can write the program, I need to find formulas for the heat capacity of a few substances: Al, Fe, BaTiO3, and Polyethylene. Ideally, I'm looking for equations that explain this behavior between 298K and 600K

Homework Equations

The formula I'm looking for is usually in the following form:
c = A+BT + CT^-2 + DT^-3

or something similar where:
c= heat capacity
T = temperature
A,B,C,D are constants

The Attempt at a Solution

I have spent some time on google, but either I'm not phrasing my search correctly or am looking in the wrong place. Does anyone have any advice on how to find these formulas? I am at a college university, so are there any good books I should check out on this matter? Thank you for any helps you can offer.

 

[rock.freak667]

Can't you just look up the values for them?

http://www.efunda.com/materials/elements/hc_table.cfm?element_id=al

or do you need an actual function to do it?

 

[Vivamus]

or do you need an actual function to do it?

Unfortunately, I do need the actual function to write this program. :(