Cambridge English: Proficiency (CPE) Masterclass SB with Online Skills and Language Practice Pack
Kathy Gude, Michael Duckworth, Louis Rogers
Proficiency Masterclass Workbook with Key and Audio CD Pack
Kathy Gude, Michael Duckworth
Proficiency Testbuilder Student Book -key Pack
M. Harrison
Proficiency Scales for the New Science Standards: A Framework for Science Instruction and Assessment, Paperback
Robert Marzano
Proficiency in personal survival techniques
International Maritime Organization
New Proficiency Passkey - Student's Book
Nick Kenny