Schmidt, G. [ca. 2011]. Relational mathematics. In Encyclopedia of mathematics and its applications [Book]. Cambridge [u.a.]: Cambridge Univ. Press.
ISO-690 (author-date, English)SCHMIDT, Gunther, 2011. Relational mathematics. Cambridge [u.a.]: Cambridge Univ. Press. Encyclopedia of mathematics and its applications, 132. ISBN 9780521762687.
Modern Language Association 9th editionSchmidt, G. „Relational mathematics“. Encyclopedia of mathematics and its applications, book, Cambridge Univ. Press, 2011.
Mohr Siebeck - Recht (Deutsch - Österreich)Schmidt, Gunther: Relational mathematics, . Encyclopedia of mathematics and its applications, Cambridge [u.a.] 2011.
Emerald - HarvardSchmidt, G. (2011), Relational mathematics, Encyclopedia of mathematics and its applications, Bd. , Cambridge Univ. Press, Cambridge [u.a.].