St. Anthony of Padua is another very popular Franciscan Saint.  
As you prepare for or are presently doing exams you might like to recite this prayer:

O glorious St. Anthony, divinely filled with the science of the saints, I place my studies under your powerful protection.   After your example let my knowledge be grounded in the Heart of Jesus and the Heart of Mary.   With the aid of your prayers I propose to perform my studies as a matter of duty, with a pure intention and in a spirit of penance.   Implore the Father of light to grant me a ready understanding, a sound judgement and a faithful memory.   Obtain for me the grace to work with constancy, patience and method.   Help me to develop the gifts I have received from God and to employ them for the greater glory.   Pray God to bless my efforts, granting me success in my studies and keeping me humble in the midst of success.   Amen.