Differential geometry and scalar gravitational waves

Following some strong argumentations of differential geometry in the Landau's book, some corrections about errors in the old literature on scalar gravitational waves (SGWs) are given and discussed. In the analysis of the response ofi nterferometers the computation is first performed in the low frequencies approximation, then the analysis is applied to all SGWs in the full frequency and angular dependences. The presented results are in agreement with the more recent literature on SGWs.