@article{PORMA_1994__51_1_47027,
     author = {Galli, A. and Sagastume, M.},
     title = {A subdirectly irreducible symmetric {Heyting} algebra which is not simple.},
     journal = {Portugaliae mathematica},
     pages = {141--146},
     publisher = {mathdoc},
     volume = {51},
     number = {1},
     year = {1994},
     zbl = {0803.06013},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/PORMA_1994__51_1_47027/}
}