1968 #s 3-6 - Sea Frontiers - Bulletin of International Oceanographic Foundation. Condition is "Acceptable".  

All show their age. #s 3 and 5 are in the best shape with some cover scratches and bends. #4 has child like scribbles on the cover which was damp at some point. The cover on #6 is lose. Both #s 4 and 6 had a damp edge at some point.  Please review all pictures and use the zoom and enlarge features to determine and confirm condition