BLAGA, Paul A. 2015. “Gerard Walschap, Multivariable Calculs and Differential Geometry, Walter De Gruyter (De Gruyter Graduate), 2015, ix+355 Pages, Paperback, ISBN 978-3-11- 036949-6”. Studia Universitatis Babeș-Bolyai Mathematica 60 (4):625-26. https://studia.reviste.ubbcluj.ro/index.php/subbmathematica/article/view/5842.