On the problem of finding small subdivision and homomorphism bases for classes of countable graphs.

Reinhard Diestel On the problem of finding small subdivision and homomorphism bases for classes of countable graphs. 21-33 1985 55 Discrete Mathematics 1 http://dx.doi.org/10.1016/S0012-365X(85)80018-2 db/journals/dm/dm55.html#Diestel85