# Specific heat capacity at constant pressure formula

I want to calculate specific heat capacity at constant pressure for a single walled carbon nanotube by using of fluctuation in enthalpy. The fluctuations were obtained from molecular dynamics simulation. I read some literature for method of calculation. I faced with two formula to calculation of specific heat capacity, but I'm not sure which is true: $$c_p=\frac{<\delta H^2>}{k_B T^2}$$ where was written in https://pubs.acs.org/doi/abs/10.1021/jp910246t (Eq. (1)) . On the other hand in the article https://journals.aps.org/prb/abstract/10.1103/PhysRevB.74.155441 (Eq.(4.1)) was mentioned different equation than above: $$c_p=\frac{<\delta H^2>}{N k_B T^2}$$