Fresnel coefficients of forward and backward waves refracting at the interface of isotropic media

The Fresnel coefficients are derived for cross- and co-polarization states of plane electromagnetic wave incident at the interface between two isotropic media. The media can support forward or backward normal waves. Based on introduction of wave type identifiers, without application of the notion of the negative refractive index, phenomena of positive and negative refractions are considered in the general case