Alessandro Stradella - The Oxford Dictionary of Music entry at xrefer notes the origins of the Flotow work. www.xrefer.com/entry/236131
Stradella: By Friedrich von Flotow - Notes origin of libretto, first production, chief characters and plot summary from Gladys Davidson's Two Hundred Opera Plots. www.intac.com/~rfrone/operas/Books/200_opera_plots/200_opera_plots.htm#046
The Standard Operaglass: Alessandro Stradella - Synopsis of the work includes composer and librettist credits. From the book by Charles Annesley. www.intac.com/~rfrone/operas/Books/Annesley-Standard/Annesley-A.htm#Alessandro
