78 

    79 

    80 

    81 @Book{Berger66,

    82   author = 	 {R.~Berger},

    83   title = 	 {{T}he {U}ndecidability of the {D}omino {P}roblem},

    84   journal = 	 {Memoirs of the American Mathematical Society},

    85   year = 	 {1966}

    86 }

    87 

    88 

    89 @Article{Robinson71,

    90   author = 	 {R.~M.~Robinson},

    91   title = 	 {{U}ndecidability and {N}onperiodicity for {T}ilings of the {P}lane},

    92   journal = 	 {Inventiones Mathematicae},

    93   year = 	 {1971},

    94   volume = 	 {12},

    95   pages = 	 {177--209}

    96 }

    97 

    98