CREATE TABLE table_name_8 (width_feet__m_ VARCHAR2, source__year_ VARCHAR2)

What is the width for hte truss with a source of zacher (1994)?
SELECT width_feet__m_ FROM table_name_8 WHERE source__year_ = "zacher (1994)"
SELECT "width_feet__m_" FROM "table_name_8" WHERE "source__year_" = "zacher (1994)"