1) http://www.grammarbank.com/must-have-to-exercise.html
2) https://www.englishclub.com/grammar/verbs-modals-have-to-must-not-quiz.htm
3) http://learn-english-today.com/lessons/lesson_contents/exercises/must-haveto_quiz1.html
4) http://mbonillo.xavierre.com/exercises/eso3/3eso2007/musthaveto1.htm