Question:
Which employer did Eugen Loderer work for in Jun, 1957?

Context:
 Eugen Loderer works for IG Metall from Jan, 1968 to Jan, 1983. 
 Eugen Loderer works for IG Metall Heidenheim from Jan, 1947 to Jan, 1959. 
 Eugen Loderer works for IG Metall Baden-Württemberg from Jan, 1959 to Jan, 1963.

Answer:
IG Metall Heidenheim