  The description of photoabsorption cross-sections of cold nuclei by
closed-form Lorentzian models of photon strength functions for photoexcitation
by electric dipole gamma-rays is considered. Systematics of the GDR parameters
are given and input parameters of different analytical models are discussed The
experimental data are compared with theoretical calculations for even-even
nuclei using criteria of minimum of both least-square value and
root-mean-square deviation factor. Simple extensions of the models with
energy-dependent widths to high gamma-ray energies $\gtrsim $ 30MeV which hold
the energy-weighted sum rule for E1 gamma-transitions in good approximation are
proposed and tested.
