@article{oai:tsukuba.repo.nii.ac.jp:00016089,
 author = {Koyama, Akira},
 issue = {2},
 journal = {Tsukuba Journal of Mathematics},
 month = {Dec},
 pages = {237--240},
 title = {A note on span under refinable maps},
 volume = {9},
 year = {1985}
}