Structural assignment of Diel-Alder adducts: an experimental and theoretical approach - Constantino, Maurício Gomes; Silva Filho, Luiz Carlos da; Cunha Neto, Alvaro; Heleno, Vladimir Constantino Gomes; Silva, Gil Valdo José da; Lopes, João Luís Callegari (Spectrochimica Acta Part A, 2004)