Tosi inʼgu chojŏl e kwanhan yŏnʼgu : Sŏul-si inʼgu ŭi kajok kyehoek mit chʻulsannyŏk = A study on urban population control : family planning and fertility with population in Seoul / Kwŏn I-hyŏk [tŭngjŏ] = by E Hyock Kwon [and others].
都市人口調節에關한硏究 : 서울市人口의家族計劃및出產力= A study on urban population control : family planning and fertility with population in Seoul / 權彝赫 [等著] = by E Hyock Kwon [and others].