Acknowledgements:

• Ms. Tamara Djordjevic for translating site into English.
• Mr. Pelcl Mirko for providing photographs and support in creating this website. Visit his website: Mirko old radio collection;
  
• Mr. Petković Jovica from Belgrade for photographs and support;
  
• Mr. Zec Radoslav from Banja Luka for photographs and information;
  
• Mr. Matić Dejan for photographs of the RUP-15 device;
  
• Mr. Popov Dejan for photographs and other material;
  
• Mr. Zoran from Banja Luka for photographs and assistance in describing radio relay devices.
  
• Mr. Miodrag Damnjanović for information, photographs and other material about devices manufactured by "Ei Pionir" Zemun.
  
• Ms. Aleksandra Jovanović for translating texts into English.