Book

Siregar, Robert Tua and Rahmadana, Muhammad Fitri and Nainggolan, Pinondang and Basmar, Edwin and Siagian, Valentine (2021) Ekonomi Industri. Yayasan Kita Menulis, Medan.

Siagian, Valentine and Rahmadana, Muhammad Fitri and Basmar, Edwin and Purba, Pratiwi Bernadetta and Nainggolan, Lora Ekana and Nugraha, Nur Arif and Siregar, Robert Tua and Lifchatullaillah, Endang and Marit, Elisabeth Lenny and Simarmata, Hengki Mangiring Parulian and Prasetya, Agustian Budi and Purba, Bonaraja (2020) Ekonomi dan Bisnis Indonesia. Yayasan Kita Menulis, Medan.