Peter G. Malischewsky, Frank Scherbaumb (2004). Love’s formula and H/V-ratio (ellipticity) of Rayleigh waves, Wave Motion
Dario Albarello, Enrico Lunedei (2009). Alternative interpretations of horizontal to vertical spectral ratios of ambient vibrations: new insights from theoretical modeling, Bull Earthquake Eng, DOI 10.1007/s10518-009-9110-0