@article{Dershowitz1975, 
     author = "Dershowitz, Nachum", 
     doi = "10.1007/BF01932689", 
     issn = "00063835", 
     journal = "BIT", 
     keyword = "loop-free algorithms,ordering,permutation generation,permutations,permutations and combinations", 
     link = "http://link.springer.com/10.1007/BF01932689", 
     month = "jun", 
     number = "2", 
     pages = "158--164", 
     title = "A simplified loop-free algorithm for generating permutations", 
     uri = "http://link.springer.com/10.1007/BF01932689", 
     volume = "15", 
     year = "1975", 
}

Problems: 404