O. P. Khanna

• General knowledge glimpses
• Master guide, Posts & Telegraphs Board Open Competitive Examination (for recruitment of telegraphists, telephone operators, sorters, clerks in Engineering and Postal Divisions and in other subordinate offices of the Posts & Telegraphs Administration)
• Master guide, Special Class Railway Apprentices' Examination
• Master guide, Subordinate Services Selection Board Open Competitive Examination for Clerks
• Master guide, UPSC Clerk's Grade Examination (including solved papers, essays, drafting, precis-writing, applied grammar, proof-correcting, tabulation, present-day India, everyday science, who's who)
• Refresher course, General knowledge current affairs who's who