Earthman's Burden
Earthman's Burden is a collection of science fiction stories by American writers Poul Anderson and Gordon R . Dickson . 
<triplet> Earthman's Burden <subj> science fiction <obj> genre <subj> Poul Anderson <obj> author <subj> Gordon R. Dickson <obj> author <triplet> Poul Anderson <subj> science fiction <obj> genre <triplet> Gordon R. Dickson <subj> science fiction <obj> genre