@Misc{BVMC:260230,
title = {Homes forts, al front : P.S.U.},
publisher = {Barcelona : Sindicat de Dibuixants Professionals U.G.T., [entre 1936 i 1939] (Graf. Ultra)},
year = {1939},
url = {https://www.cervantesvirtual.com/obra/homes-forts-al-frontpsu}
}