## Influence of uniaxial and hydrostatic pressures and shear stress $\sigma_{5}$ on the phase transition and thermodynamic properties of quasi-one-dimensional ferroelectrics of the CsH$_2$PO$_4$ type

Within the framework of the modified proton ordering model for the quasi-one-dimensional hydrogen bonded ferroelectrics of the CsH$_2$PO$_4$ type with taking into account the linear in the strains $\varepsilon_1$, $\varepsilon_2$, $\varepsilon_3$, and $\varepsilon_5$ contributions into the energy of the proton subsystem, without tunneling, using the two-particle cluster approximation, we study the influence of uniaxial pressures $p_{i}$, hydrostatic pressure $p_{h}$, and shear stress $\sigma_{5}$ on the phase transition, polarization, transverse dielectric permittivity, elastic constants a