@article{Fujisawa1959, 
     author = "Fujisawa, T.", 
     doi = "10.1109/TCT.1959.1086556", 
     issn = "0096-2007", 
     journal = "IRE Transactions on Circuit Theory", 
     number = "3", 
     pages = "261--266", 
     title = "On a Problem of Network Topology", 
     volume = "6", 
     year = "1959", 
}

Problems: 472