https://books.google.com/books?id=ZiQDAAAAMBAJ&printsec=frontcover&dq=popular+science+1949&hl=en&sa=X&ved=0ahUKEwicl4ntlbfRAhXERCYKHVbqDg0Q6AEIJDAC#v=onepage&q=popular%20science%201949&f=false

https://books.google.com/books?id=ZiQDAAAAMBAJ&printsec=frontcover&dq=popular+science+1949&hl=en&sa=X&ved=0ahUKEwicl4ntlbfRAhXERCYKHVbqDg0Q6AEIJDAC#v=onepage&q=popular%20science%201949&f=false