Valma, E., Tamosiunaite, M., Tamosiunas, S., Tamosiuniene, M. and Zilinskas, M. 2011. Variation of Radio Refractivity with Height above Ground. Elektronika ir Elektrotechnika. 111, 5 (Jun. 2011), 23-26. DOI:https://doi.org/10.5755/j01.eee.111.5.349.