Phosphorus production in submerged-arc furnace.
Translated into Telugu by <a href="//commons.wikimedia.org/wiki/User:Mekala_Harika" title="User:Mekala Harika">User:Mekala Harika</a>
2019-03-24
Vollrath Hopp – Grundlagen der chemischen Technologie. 4th edition 2001, p. 300 by <a href="//commons.wikimedia.org/wiki/User:Fred_the_Oyster" title="User:Fred the Oyster">Fred the Oyster</a>