An Anthology of Lyric Pieces for Trumpet and other instuments is one of the most helpful studies I have come across.
Firs,t it’s all about playing songs, and that’s the reason we play, to play melodies. This book will help you understand a phrase, control the breath and intonation. . It is in treble clef but that is also good to be able to read in treble clef .The book is filled with operatic songs and intermezzos. Author Jay Rizzetto is one of the bay areas leading trumpet players/ teacher. We have had conversations on the merits of just playing a tune. After all that’s what music is all about!
http://pasquina.com/