P. Lallemand, P. Simova, G. Bret, Pressure-Induced Line Shift and Collisional Narrowing in Hydrogen Gas Determined by Stimulated Raman Emision, Physics Review Letters (17) 1239-1241 (1966)

N. Bloembergen, G. Bret, P. Lallemand, A. Pine, P. Simova, Controlled stimulated Raman Amplification and Oscillation in Hydrogen Gas, IEEE J. QE-3, 199-201 (1967)

N. Kirov, P. Simova, The Potential Barriers of the PAA Molecules in Crystal Nematic and Isotropic Phases, Physics Letters, v. 37A (1) 25 October 1971, 51-52

N. Kirov, P. Simova, Infrared absorption spectra of liquid crystals - 1, Spectrochimica Acta, Pergamon Press, Printed in Northern Ireland (29A) 55-62 (1973)

P. Simova, N. Kirov, IR Absorption Spectra of Liquid Crystals, Advances in Molecular Relaxacions Processes (5) 233-243 (1973)

N. Kirov, P. Simova, On the Temperature dependence of IR Integral Intensity in Crystal, Nematic and Isotropic P-Azoxyanisole (PAA), Доклады БАН, 26(8) 1013-1015 (1973)

P. Simova, N. Kirov, Rotational Diffusion of Nonassociated Molecules in Pure Liquids and in Dilute Solutions, Българки физически журнал, 1(1) 21-30 (1974)

P. Simova, N. Kirov, Infrared Spectra of Liquid Crystals - III Rotational Diffusion in Smectic and Cholesteric Mesophase, Spectroscopy Letters, 8(8) 561-570 (1975)

N. Kirov, P. Simova, Infrared Absorption Spectra of Liquid Crystals, Molecular Crystals and Liquid Crystals (30) 59-71 (1975)

P. Simova, N. Kirov, Anizotropy of Rotational Diffusion in Nematic and Isotropic Phases, Spectroscopy Letters, 7(2) 55-61 (1974)

N. Kirov, P. Simova, M. Sabeva, Depolarization of Light Scattered in Nematic Liquid Crystals, Molecular Crystals and Liquid Crystals (33) 189-194 (1976)

P. Simova, M. Petrov, N. Kirov, Coherent Light Diffraction in a Smectic C Liquid Crystal, Molecular Crystals and Liquid Crystals, Gordon and Breach Science Publishers Ltd, Printed in Holland (42) 295-305 (1977)

N. Kirov, P. Simova, S. Sainov, Broadening of IR Absorption Bands of p-Methoxybenzylidene, p, n-Butilaniline (MBBA) under the influence of an A. C. Electric Field, Spectroscopy Letters, 10(10) 783-789 (1977)

P. Simova, N. Kirov, Determination of Elastic Constant K33 for Some Nematic Liqued Crystals with Strong Positive Dielectric Anisotropy by MNeans of IR Absorption Spectroscopy, Molecular Crystals and Liquid Crystals (46) 137-145 (1978)

N. Kirov, P. Simova, H. Ratajczac, Influence of a.c. Electric Field on IR Spectra of some nematic Liquid Crystals with Positive and Negative Dielectric Anisotropy, Journal of Molecular Structure (46) 487-493 (1878)

P. Simova, N. Kirov, M. Fontana, H. Ratajczak, Atlas of Vibrational Spectra of Liquid Crystals, World Scientific, Singapore (1988)

I. Savatinova, P. Simova, L. Tsonev, Losses in diffused optical waveguides, Applied physics (20) 219–224 (1979)