Massive spin-0 and spin-1 wave equations. 1, Second-order equations
Loide, Rein-Karl
1987
https://www.ester.ee/record=b1260527*est
Massive spin-0 and spin-1 wave equations. 2., First-order equations
Loide, Rein-Karl
1987
https://www.ester.ee/record=b1260530*est
Some remarks on first order wave equations
Loide, Kadrin
;
Loide, Rein-Karl
1977
https://www.ester.ee/record=b1274745*est