@book {Maas1970,
	title = {Sancti Romani Melodi Cantica. 2. Cantica Dubia},
	volume = {2},
	year = {1970},
	author = {Maas, P. Trypanis, C. A.}
}
@book {Maas1963,
	title = {Sancti Romani Melodi Cantica. 1. Cantica Genuina},
	volume = {1},
	year = {1963},
	author = {Maas, P. Trypanis, C. A.}
}
