@article{Wang1996, 
     author = "Wang, Terry Min Yih and Savage, Carla D.", 
     doi = "10.1137/S089548019528143X", 
     issn = "0895-4801", 
     journal = "SIAM Journal on Discrete Mathematics", 
     link = "http://link.aip.org/link/SJDMEC/v9/i4/p654/s1\&Agg=doi http://epubs.siam.org/doi/abs/10.1137/S089548019528143X", 
     month = "nov", 
     number = "4", 
     pages = "654--673", 
     title = "A Gray Code for Necklaces of Fixed Density", 
     uri = "http://link.aip.org/link/SJDMEC/v9/i4/p654/s1&Agg=doi", 
     volume = "9", 
     year = "1996", 
}

Problems: 328