▁ 1 9 2 9 ▁and ▁May ▁ 1 9 3 0 . ▁He ▁also ▁tra ve led ▁to ▁New ▁York ▁City ▁for ▁recording ▁sessions ▁in ▁January ▁and ▁February ▁ 1 9 3 4 . ▁Robert ▁Johnson ▁recorded ▁his ▁only ▁sessions , ▁for ▁AR C , ▁in ▁San ▁Antonio ▁in ▁ 1 9 3 6 ▁and ▁Dallas ▁in ▁ 1 9 3 7 . ▁ ▁Sub sequently , ▁the ▁early ▁D elta ▁bl ues ▁( as ▁well ▁as ▁other ▁gen res ) ▁were ▁extens ively ▁recorded ▁by ▁John ▁L om ax ▁and ▁his ▁son ▁Alan ▁L om ax , ▁who ▁cr iss cross ed ▁the ▁southern ▁U . S . ▁recording ▁music ▁played ▁and ▁s ung ▁by ▁ordinary ▁people , ▁helping ▁establish ▁the ▁canon ▁of ▁gen res ▁we ▁know ▁today ▁as ▁American ▁folk ▁music . ▁Their ▁record ings , ▁number ing ▁in ▁the ▁thousands , ▁now ▁res ide ▁in ▁the ▁Smith son ian ▁Institution . ▁According ▁to ▁D ixon ▁and ▁God rich ▁( 1 9 8 1 ) ▁and ▁Le ad bit ter ▁and ▁S la ven ▁( 1 9 6 8 ), ▁Alan ▁L om ax ▁and ▁the ▁Library ▁of ▁Congress ▁research ers ▁did ▁not ▁record ▁any ▁D elta ▁bl ues men ▁or ▁women ▁prior ▁to ▁ 1 9 4 1 , ▁when ▁he ▁recorded ▁Son ▁House ▁and ▁Will ie ▁Brown ▁near ▁Lake ▁C orm or ant , ▁Mississippi , ▁and ▁M ud dy ▁W aters ▁at ▁Sto v all , ▁Mississippi . ▁However , ▁this ▁claim ▁has ▁been ▁disput ed ,