Reference:
  Author: Gunnar von Heijne
  Title: "Membrane protein structure prediction. Hydrophobicity analysis and the positive-inside rule"
  Journal: Journal of Molecular Biology
  Year: 1992
  Volume: 225
  Number: 2
  Pages: 487-94
  DOI: 
  PMID: 1593632
  URL: http://www.sciencedirect.com/science/article/pii/002228369290934C
  eprint: 
