Start with the tables available from the Minco.com site.
Pick and print a table for Platinum:PE TCR=3.85e-3, R0=100,temp range
20C to 220C inclusive.
Minco indicates A=0.0039083, B=-5.775e-07, C=-4.183e-12.
Put the data in a spreadsheet and do an XY error curve, tabular data
VS equation.
Note that i had to fiddle with B and C to get a reasonable fit, and
one is challenged to get two digits of significance for C.
See attached pic of error giraffe.