Table: william_h_christensen
Columns: name
background
title
appointment
presentation_of_credentials

Question: Who presented their credentials at an unknown date?
SQL: SELECT "name" FROM william_h_christensen WHERE "presentation_of_credentials" = 'unknown'

Question: When did Robert G. Miner present his credentials?
SQL: SELECT "presentation_of_credentials" FROM william_h_christensen WHERE "name" = 'robert g. miner'

Question: When was William A. Costello appointed?
SQL: SELECT "appointment" FROM william_h_christensen WHERE "name" = 'william a. costello'

Question: Who was appointed on October 24, 1997?
SQL: SELECT "name" FROM william_h_christensen WHERE "appointment" = 'october 24, 1997'

Question: What was Anthony D. Marshall's title?
SQL: SELECT "title" FROM william_h_christensen WHERE "name" = 'anthony d. marshall'