This music can be instantly opened with the following apps:
About "Canonic Sonatas, Book II"
High-quality Digital sheet music for two trombones, Book II,
IMPORTANT: This item doesn't include separate parts. Both instruments have to read from the same part in a way that when the first part reaches the bar marked with “Canon,” the second part starts playing; then both parts keep playing together a few bars apart until the end of the piece, hence the resulting “Canon.