The O17(p,α)N14 and O17(p,γ)F18 reactions are of paramount importance for the nucleosynthesis in a number of stellar sites, including red giants (RGs), asymptotic giant branch (AGB) stars, massive stars, and classical novae. In particular, they govern the destruction of O17 and the formation of the short-lived radioisotope F18, which is of special interest for γ-ray astronomy. At temperatures typical of the above-mentioned astrophysical scenario, T=0.01-0.1 GK for RG, AGB, and massive stars and T=0.1-0.4 GK for a classical nova explosion, the O17(p,α)N14 reaction cross section is dominated by two resonances: one at about ERcm=65 keV above the F18 proton threshold energy, corresponding to the EX=5.673 MeV level in F18, and another one at ERcm=183 keV (EX=5.786 MeV). We report on the indirect study of the O17(p,α)N14 reaction via the Trojan Horse method by applying the approach recently developed for extracting the strength of narrow resonance at ultralow energies. The mean value of the strengths obtained in the two measurements was calculated and compared with the direct data available in literature. This value was used as input parameter for reaction-rate determination and its comparison with the result of the direct measurement is also discussed in the light of the electron screening effect
