Coba jelasin Kalkulus vektor dari Persamaan gelombang elektromagnetik dong

P. C. Matthews Vector Calculus, Springer 1998, ISBN 3-540-76180-2

H. M. Schey, Div Grad Curl and all that: An informal text on vector calculus, 4th edition (W. W. Norton & Company, 2005) ISBN 0-393-92516-1.