 Complete the following phrase:  In addition to some 600 articles published in more than 30 periodicals, Būčys published a number of separate books on various topics. He published a collection of his articles as separate books Tikėjimo dalykai in 1913 and Gyvenimo pagrindas in 1931. His most important work is a three-volume theological work aimed at an average priest and school graduate. The three volumes on God the Creator, Jesus Christ, and the Holy Spirit were published in 19291932. His popular works include books about the 