@Book{ lastname_HL69,
	author = "H. Hermes and J.P. LaSalle",
	title = "{Functional analysis and time optimal control.}",
	publisher = "{Mathematics in Science and Engineering. 56. New York-London: Academic Press. VIII}",
	year = "1969"
}

@Article{ lastname_Mae04,
	author = "Roswitha M{\"a}rz",
	title = "{Solvability of linear differential algebraic equations with properly stated leading terms.}",
	journal = "Result. Math. ",
	volume = "45",
	number = "1-2",
	pages = "88--105",
	year = "2004" }"
}