Willis, W. R. (1979). 200 years and still counting: Past, present and future of the sunday school. Victor Books.
Chicago-viite (17. p.)Willis, Wesley R. 200 Years and Still Counting: Past, Present and Future of the Sunday School. Illinois: Victor Books, 1979.
MLA-viite (9. p.)Willis, Wesley R. 200 Years and Still Counting: Past, Present and Future of the Sunday School. Victor Books, 1979.
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