N. G. Deshpande, J.F. Gunion, B. Kayser, F. I. Olness
Left-right symmetric electroweak models with triplet Higgs
Phys. Rev. D44 (1991) 837–858 (requires PRD subscription)
(An example for models in which Majorana mass terms for neutrinos
are generated by triplet Higgs fields, cf. problem 2b on
problem sheet 1.)