The dataset used in the paper:
  Hisanori Kiryu, Yasuo Tabei, Taishin Kin, and Kiyoshi Asai.
  Murlet: a practical multiple alignment tool for structural RNA sequences.
  submitted to Bioinformatics.

dataset1_stockholm.txt: 
  85 multiple alignments extracted from Rfam7.0 database. The number of
  families is 17. For each family, there are 5 sub alignments of 10
  sequences.

dataset2_stockholm.txt: 
  188 multiple alignments of 4 sequences taken from the Hammerhead_3
  ribozyme family in the Rfam7.0 database.

Reference:
  Hisanori Kiryu, Yasuo Tabei, Taishin Kin, and Kiyoshi Asai.
  Murlet: a practical multiple alignment tool for structural RNA sequences.
  submitted to Bioinformatics.

  Sam Griffiths-Jones, Alex Bateman, Mhairi Marshall, Ajay Khanna, and
  Sean R Eddy. Rfam: an RNA family database. 
  Nucleic Acids Res, 31(1):43941, 2003.