@article{oai:tsukuba.repo.nii.ac.jp:00015695,
 author = {Hardie, K. A.},
 issue = {1},
 journal = {Tsukuba Journal of Mathematics},
 month = {Jun},
 pages = {85--98},
 title = {Approximating the homotopy sequence of a pair of spaces},
 volume = {15},
 year = {1991}
}