 growth decai curv scientif citat in rapidli advanc scientif disciplin contribut supersed older thi select favor literatur observ distribut footnot citat disciplin ag articl cite howev ag distribut citat depend rate growth disciplinari literatur the growth literatur select favor articl separ assumpt hold exponenti model expand clarifi earlier find price thi model reason good fit ag-distribut footnot disciplin applic citat sociolog tend refer older articl natur scienc a paramet model measur degre select favor articl estim compar studi commun system disciplin 