Sources

1) Source: The Russian Primary Chronicle "We are the envoys from the Russian nation: Ivar, envoy of Igor', Great Prince of Rus', and the general envoys as follows: Vefast representing Svyatoslav, son of Igor'...But Igor' did not heed them, and the Derevlians came forth from the city of Iskorosten' and slew Igor' and his company, for the number of the latter was few. So Igor' was buried, and his tomb is near the city of Iskorosten' in Dereva even to this day". Reference: 6452 (944) (Data from secondary evidence)
2) Source: The Russian Primary Chronicle "On his deathbed, Rurik bequeathed his realm to Oleg, who belonged to his kin, and entrusted to Oleg's hands his son Igor', for he was very young.". Reference: 6378-6387 (870-879) (Questionable reliability of evidence)
3) Source: The Russian Primary Chronicle "As Igor' grew up, he followed after Oleg, and obeyed his instructions. A wife, Olga by name, was brought to him from · Pskov.". Reference: 6411 (903)
4) Source: The Russian Primary Chronicle "But Olga was in Kiev with her son, the boy Svyatoslav.". Reference: 6452 (944) (Data from secondary evidence)
5) Source: The Russian Primary Chronicle "Three days later Olga died". Reference: 6477 (969) (Data from secondary evidence)
6) Source: The Russian Primary Chronicle "Olga shut herself up in the city of Kiev with her grandsons, Yaropolk, Oleg, and Vladimir.". Reference: 6476 (968) (Data from secondary evidence)
7) Source: The Russian Primary Chronicle "When spring came, in 972 Svyatoslav approached the cataracts, where Kurya, Prince of the Pechenegs, attacked him; and Svyatoslav was killed.". Reference: 6480 (972) (Data from secondary evidence)