@article{MS2_1983__52_166842,
     author = {Ivan Tafteberg Jakobsen},
     title = {On a certain homomorphism properties of graphs {II.}},
     journal = {Mathematica Scandinavica},
     pages = {229--261},
     publisher = {mathdoc},
     volume = {52},
     year = {1983},
     zbl = {0566.05049},
     url = {http://geodesic.mathdoc.fr/item/MS2_1983__52_166842/}
}