http://www.battlefield.ru/library/battles/
battle13_04.html
'Even before the Voronezh-Kastornoe operation commenced, the Stavka was planning to expand the strategic offensive's scope. While Soviet forces were advancing westward along the Voronezh and Rostov axes, on 20 and 23 January, the Stavka ordered the Voronezh and Southwestern Fronts to conduct two new operations code-named STAR and GALLOP, respectively. In STAR the Voronezh Front's forces were to attack on 2 February, capture Kharkov, and, if conditions permitted, exploit as far as Kremenchug on the Dnieper River. In GALLOP the Southwestern Front's forces were to advance on 29 January, seize Voroshilovgrad and Stallion, and reach Zaporozh'e on the Dnieper and Mariupol' on the Sea of Azov. The Stavka's strategic aim was nothing short of the destruction of already weakened German Army Group Don and the encirclement of German Army Group 'A' in the Rostov and Mius River regions. The preparations for operations STAR and GALLOP established a new planning pattern for the Winter Campaign. Given the severe time constraints and the extremely fluid situation, the Stavka formulated its new operational plans from the march while current operations were being prepared or conducted. True to this pattern and because of the spectacular successes achieved by Soviet forces around Voronezh, on 26 January the Stavka added Kursk to the list of objectives to be captured in operation STAR.'
