Daniels, W. H. (1885). Dr. Cullis and his work: Twenty years of blessing in answer to prayer ; a history of the hospitals, schools, orphanages, churches and missions raised up and supported by the hand of the Lord through the faith and labors of Charles Cullis of Boston, U.S.A. Boston: Willard Tract Repository.

Daniels, William Haven. Dr. Cullis and His Work: Twenty Years of Blessing in Answer to Prayer ; a History of the Hospitals, Schools, Orphanages, Churches and Missions Raised Up and Supported By the Hand of the Lord Through the Faith and Labors of Charles Cullis of Boston, U.S.A. Boston: Willard Tract Repository, 1885.

Daniels, William Haven. Dr. Cullis and His Work: Twenty Years of Blessing in Answer to Prayer ; a History of the Hospitals, Schools, Orphanages, Churches and Missions Raised Up and Supported By the Hand of the Lord Through the Faith and Labors of Charles Cullis of Boston, U.S.A. Boston: Willard Tract Repository, 1885.