Yield Stress Data In material database editor of CII

In material database editor of CII, Yield stress values are filled with different values corresponding to the reference temperature
ASTM or ASME Code just indicates a single yield stress value for each material.
I`m wondering which code, database or calculations are used in CAESAR II database.

Broken,
I didn't look up all the codes, but I think you can find the table of yield stress(also strength) at temperature in ASME BPVC Sec.II