Step 10 - I libri

Bibliografia storica: 

Rivista: Radio Electronics (1959), pag 56 [1]
Rivista: Popular Electronics (1959), pag 136 [2]
Libro: Transistor Techniques, Gernsback Library (1959), pag 17 [3]
Libro: Official Gazette di United States. Patent Office (1962), volume 781, pag 1185 [4]
Libro: Index of Patents Issued Di United States. Patent Office (1963), pag 348 [5]
Libro: Catalog of Copyright Entries. Third Series: 1972: January-June Di Library of Congress. Copyright Office (1972), volume 26, pag 1492 [6]

Rivista: 73 Magazine, Amateur Radio (1967), pag. 16 [7]

[1]  https://worldradiohistory.com/Archive-Radio-Electronics/50s/1959/Radio-Electronics-1959-02.pdf 
[2]  https://worldradiohistory.com/Archive-Poptronics/50s/59/Pop-1959-04.pdf 

[3] https://archive.org/details/Transistor_Techniques_Gernsback_Library_1959/page/n17/mode/2up 
[4] https://books.google.it/books?id=WFobAQAAMAAJ&pg=PA1185&lpg=PA1185&dq=transistor+tester+sol+zechter&source=bl&ots=qtRyJQNQTl&sig=ACfU3U3TzDws2R0Z8qZF7i-hEO4GEq8g7Q&hl=it&sa=X&ved=2ahUKEwjFpMm1pfXsAhVooXIEHYKRBF8Q6AEwAHoECAIQAg#v=onepage&q=transistor%20tester%20sol%20zechter&f=false 
[5] https://books.google.it/books?id=Q9cQsmm5AJIC&pg=PA348&lpg=PA348&dq=sol+zechter+transistor+tester&source=bl&ots=Z2yolCTOh5&sig=ACfU3U23Wrv2VNKQ03LbKj1IBP1ESO0sGg&hl=it&sa=X&ved=2ahUKEwi4hOeSpvXsAhXsknIEHbPpB6QQ6AEwA3oECAgQAg#v=onepage&q=sol%20zechter%20transistor%20tester&f=false 
[6] https://books.google.it/books?id=Hj4hAQAAIAAJ&pg=PA1492&lpg=PA1492&dq=Roger+Boatman+%26+Associates+Inc+transistor+tester&source=bl&ots=3UAfAKebKb&sig=ACfU3U1Cpn6wZBKZZ-HhQnzvSO-EYPjtfA&hl=it&sa=X&ved=2ahUKEwi0u_7apvXsAhXqlHIEHWvZB6sQ6AEwBXoECAkQAg#v=onepage&q=Roger%20Boatman%20%26%20Associates%20Inc%20transistor%20tester&f=false 

[7] http://www.arimi.it/wp-content/73/01_January_1967.pdf