Widada, Wahyu. “METODE TRACKING KECEPATAN ROKET MENGGUNAKAN TRANSPONDER DOPPLER DUA-FREKUENSI (ROCKET SPEED TRACKING METHOD USING TWO-FREQUENCY DOPPLER TRANSPONDER)”. Indonesian Journal of Aerospace, vol. 11, no. 1 Juni, Dec. 2013, pp. 59-66, https://ejournal.brin.go.id/ijoa/article/view/12314.