https://www.myengineers.com.ng/2014/07/22/statement-by-the-council-for-the-regulation-of-engineering-in-nigeria-coren-on-the-quality-of-cement-in-use-in-the-construction-industry-in-nigeria/
STATEMENT BY THE COUNCIL FOR THE REGULATION OF ENGINEERING IN NIGERIA [COREN] ON THE QUALITY OF CEMENT IN USE IN THE CONSTRUCTION INDUSTRY IN NIGERIA