@article{10_14708_ma_v17i31_1763,
     author = {Henryk Brzeskwiniewicz},
     title = {E-optimality of {PBB} designs with two associate classes},
     journal = {Mathematica Applicanda},
     pages = { 39--46},
     publisher = {mathdoc},
     volume = {17},
     number = {31},
     year = {1989},
     doi = {10.14708/ma.v17i31.1763},
     language = {pl},
     url = {http://geodesic.mathdoc.fr/articles/10.14708/ma.v17i31.1763/}
}