@article {zbMATH06132858,
	title = {First variation formula for discrete variational problems in two independent variables.},
	journal = {Rev. R. Acad. Cienc. Exactas F{\'\i}s. Nat., Ser. A Mat., RACSAM},
	volume = {106},
	number = {1},
	year = {2012},
	note = {<p>n/a</p>
},
	pages = {111{\textendash}135},
	publisher = {Springer, Milan; Real Academia de Ciencias Exactas, F\'{\i}sicas y Naturales, Madrid},
	abstract = {<p>n/a</p>
},
	issn = {1578-7303; 1579-1505/e},
	doi = {10.1007/s13398-011-0034-6},
	author = {Ana Cristina {Casimiro} and C{\'e}sar {Rodrigo}}
}
