SET @pfx = 'A%';

SELECT page_title

FROM page AS main

WHERE EXISTS (SELECT 1

              FROM page AS talk

              JOIN templatelinks ON talk.page_id = tl_from

              WHERE talk.page_namespace = 1

                AND talk.page_title = main.page_title

                AND tl_from_namespace = 1

                AND tl_namespace = 10

                AND tl_title='WikiProject_Biography')

  AND main.page_namespace = 0

  AND main.page_title RLIKE '^[[:alpha:]]+_[[:upper:]]\\._[[:alpha:]]+$'

  AND main.page_title LIKE @pfx

  AND NOT EXISTS (SELECT 1

                  FROM page AS other

                  WHERE other.page_namespace = 0

                    AND other.page_title != main.page_title

                    AND other.page_title LIKE @pfx

                    AND SUBSTRING_INDEX(other.page_title, '_', 1) = SUBSTRING_INDEX(main.page_title, '_', 1) -- first word matches

                    AND SUBSTRING_INDEX(other.page_title, '_', -1) = SUBSTRING_INDEX(main.page_title, '_', -1) -- last word matches

                    AND other.page_title LIKE '%\\_%') -- at least two words in other

LIMIT 500;

​