I ran across this youtube channel Saturday. It has some in depth and very well researched videos on the history of military uniforms and camo patterns in the US and other countries.
The video above covers the history of ERDL camo, most famously used during the Vietnam war. I have collected ERDL ( say it as ERDUL) uniforms for many years. It’s not easy to get since it was not as widely issued as the OD jungle uniform. Below is one of my sets made in 1973. This set was never issued and worn. The ERDL patter was not used for many years and eventually was used to develop the Woodland pattern.