@article{MS2_1972__31_166281,
     author = {Ivan Tafteberg Jakobsen},
     title = {On {Certain} {Homomorphism} {Properties} of {Graphs} {I.}},
     journal = {Mathematica Scandinavica},
     pages = {379--404},
     publisher = {mathdoc},
     volume = {31},
     year = {1972},
     zbl = {0258.05126},
     url = {http://geodesic.mathdoc.fr/item/MS2_1972__31_166281/}
}