@article{10_4064_fm_62_3_301_308,
     author = {Jerzy P{\l}onka},
     title = {Some remarks on sums of direct systems of algebras},
     journal = {Fundamenta Mathematicae},
     pages = {301--308},
     publisher = {mathdoc},
     volume = {62},
     number = {3},
     year = {1968},
     doi = {10.4064/fm-62-3-301-308},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/fm-62-3-301-308/}
}