@article{10_1017_S0017089501010060,
     author = {Almeida, Jorge and Trotter, Peter G.},
     title = {Hyperdecidability of pseudovarieties of orthogroups},
     journal = {Glasgow mathematical journal},
     pages = {67--83},
     year = {2001},
     volume = {43},
     number = {1},
     doi = {10.1017/S0017089501010060},
     url = {http://geodesic.mathdoc.fr/articles/10.1017/S0017089501010060/}
}