2 .
Temperature and momentum dependence of phonon energies in superfluid He $^4$
50
)
4 .
Simultaneous phenomenon of antiferroelectricity and ferroelectricity in KDP-type crystals
7 ,
191
)
5 .
Transverse piezoelectric properties of KH $ _2$ PO $ _4$ type crystals
47 ,
57
)