17 Plane Crystallographic groups

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• Crystallography and Cohomology of Groups
  
  • Howard Hiller
  • The American Mathematical Monthly, Vol. 93, No. 10 (Dec., 1986), pp. 765-779
• The Orbifold Notation for Two-Dimensional Groups
  
  • John H. Conway and Daniel H. Huson
    
  • Structural Chemistry, Volume 13, Numbers 3-4, August 2002 , pp. 247-257(11)
    
• The Plane Symmetry Groups: Their Recognition and Notation
  
  • Doris Schattschneider
  • The American Mathematical Monthly, Vol. 85, No. 6 (Jun. - Jul., 1978), pp. 439-450
• • R. L. E. Schwarzenberger