@article{oai:ir.kagoshima-u.ac.jp:00006983,
 author = {SAKAI, Koukichi},
 journal = {鹿児島大学理学部紀要, Reports of the Faculty of Science, Kagoshima University},
 month = {Dec},
 pages = {1--7},
 title = {On Graphs Having Exact Three Vertices with the Same Degree},
 volume = {31},
 year = {1998}
}