@article{Sawada2013, 
     author = "Sawada, Joe and Williams, Aaron", 
     doi = "10.1016/j.tcs.2012.01.013", 
     issn = "03043975", 
     journal = "Theoretical Computer Science", 
     month = "Sep", 
     pages = "46--54", 
     publisher = "Elsevier", 
     title = "A Gray code for fixed-density necklaces and Lyndon words in constant amortized time", 
     volume = "502", 
     year = "2013", 
}

Problems: 449