《여름이었다》（夏天）是由JAEHA (재하) 和 Chan共同创作的一张专辑。这张专辑融合了多种乐器的美妙演奏，包括The TRINITY负责的钢琴 电吉他 贝斯 合成器和鼓，以及나원호演奏的电吉他和原声吉他。和声部分由JAEHA (재하)、Chan 和 려진共同完成。专辑的摄影由hidongki负责 视觉设计由LEERYAN完成 录音和混音工作则由황세현和전찬민在우대패밀리 찬민이방完成 母带处理由권남우在821 Sound Mastering完成。여름이었다Written by JAEHA, The TRINITY, ChanComposed by JAEHA, The TRINITY, ChanArranged by The TRINITYChorus by JAEHA, Chan, 려진Piano by The TRINITYElectric Guitar by 나원호Acoustic Guitar by 나원호Bass by The TRINITYSynth by The TRINITYDrum by The TRINITYPhotography by hidongkiArtwork by LEERYANRecorded by 황세현 @우대패밀리 찬민이방Mixed by 전찬민 @우대패밀리 찬민이방Mastered by 권남우 at 821 Sound Mastering