"Individual volumes are also part of 60,10=1968; 61,10=1969; 62,10=1970 usw. von "AWWA yearbook"
"Individual volumes are also part of 67,11,2=1975/76; 68,11,2=1977 usw. von "Journal. Buyers' guide / American Water Works Association"
"Individual volumes are also part of 1=34; 2=35; 3=36 usw. von "Proceedings / American Water Works Association"