Complex sentence: Contrary to western sources, official Soviet designations did not include constructors' names (e.g. Yakovlev Yak-1), only abbreviations (i.e. Yak-1) however initially full names like Yakovlev-1 were occasionally used.
Split into simpler sentences: Contrary to western sources, official Soviet designations did not include constructors' names (e.g. Yakovlev Yak-1), only abbreviations (i.e. Yak-1). Initially full names like Yakovlev-1 were occasionally used.