Anderssen variation (5... Be7) in Evans Gambit: what classic book?
Although not "classics" the following two books have significant coverage of the 5...Be7 line of Evans Gambit...
Play The Evans Gambit by Tim Harding and Bernard Cafferty (Chapt.2 - 25 pages)
https://www.amazon.com/Play-Evans-Gambit-Tim-Harding/dp/1857441192/ref=sr_1_1?crid=2WQH4CDQEEXXG&dchild=1&keywords=play+the+evans+gambit&qid=1614880632&sprefix=play+the+evans%2Caps%2C218&sr=8-1
Italian Game and Evans Gambit by Jan Pinski (Chapt.5 - 13 pages)
https://www.amazon.com/Italian-Game-Evans-Gambit-Pinski/dp/185744373X/ref=sr_1_1?crid=2QVCFYVGX75SY&dchild=1&keywords=italian+game+and+evans+gambit&qid=1614881044&sprefix=italian+game+and+evans+gambit%2Caps%2C220&sr=8-1