00297    a2200109   4500082001700000100001800017245003700035260005000072300002300122650001500145650002700160  a621.384bLEN  aLenk, John D.  aElectronic navigationbmade easy  aNew YorkbJohn F. Rider publisherc1964g1964  aviii, 167p.c21cm.  aNavigation  aElectronic Engineering