1. Chartrand G, Erwin D, Harary F, Zhang P (2001) Radio labelings of graphs. Bull Inst Combin Appl 33:77–85
2. Chartrand G, Erwin D, Harary F, Zhang P (2005) A graph labeling problem suggested by FM channel restrictions. Bull Inst Combin Appl 43:43–57
3. Chen L, Peng J, Ralescu DA (2019) Uncertain vertex coloring problem. Soft Comput 23(4):1337–1346
4. Diarmid CM (2001) Discrete mathematics and radio channel assignment. In: Recent advances in theoretical and applied discrete mathematics. Springer, pp 27–63
5. Griggs JR, Yeh RK (1992) Labeling graphs with a condition at distance 2. SIAM J Discrete Math 5:586–595